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Names ____________________________________________________________ Famous Comets (an activity from NASA’s STARDUST Mission: Think SMALL in a Big Way Guide) This activity has two parts. In the first part, you will research the significance of a specific comet. In the second part, you will write a story based on the facts surrounding your comet. You will work in teams of two to four students. Part, the First Comet Research Team Worksheet Team Roles Decide which team member will perform each of the following roles (if you don’t have four in your group, one or two members can do two jobs): Recorder: Records the results of the team’s research. Computer Operator: Uses the computer to navigate the Internet and print out any essential materials. Literary Supervisor: Records team’s input for the story. Reporter: Presents the team’s story to the rest of the class. Research Using the Internet, answer the questions on the next page. Have the recorder write down what the team learns. Each of the computers in the classroom has a folder called “Comets” with websites that will help you select your comet and find out more information about that comet. We have selected Comet _____________________________________________ 1. What makes this comet unique? __________________________________________________________________ __________________________________________________________________ 2. How long is this comet’s period? __________________________________________________________________ __________________________________________________________________ 3. What major events in history have happened when the comet has appeared? __________________________________________________________________ __________________________________________________________________ 4. How did this comet change the way astronomers think about comets or the Solar System? __________________________________________________________________ __________________________________________________________________ 5. Who discovered the comet? From what country was the discoverer? Was the discoverer a professional or amateur astronomer? __________________________________________________________________ __________________________________________________________________ 6. Print out a picture of the comet. Label its coma, gas tail, dust tail, and nucleus (if visible). 7. What was the most recent great comet? __________________________________________________________________ __________________________________________________________________ 8. What comets will appear in the night sky over the next three years? __________________________________________________________________ __________________________________________________________________ Part, the Second Using the information about your comet, you will write a story based on the facts surrounding your comet. Use the following writing prompts to help your team write a two-page story about your comet. Have the Literary Supervisor write the story as the rest of the team provides ideas and suggestions. Base your story on facts and science concepts. Here are some suggestions. Imagine you are a reporter writing a headline story about sighting this comet. Imagine that you belong to another culture in another century when your comet appears. Describe what you see, what you think it is, and how you feel. Imagine you are an amateur astronomer watching the night sky when you think you discover a comet. How do you feel? Whom do you tell? Imagine you are the comet. Talk about where you would travel during your entire orbit. Think of your own story! Illustrate your story with the photo you printed of your comet. Make sure that its parts are labeled. Famous Comets! http://amazing-space.stsci.edu/resources/explorations/comets/lesson/facts... On July 23, 1995, an unusually large and bright comet was seen outside of Jupiter's orbit by Alan Hale of New Mexico and Thomas Bopp of Arizona. Careful analysis of Hubble Space Telescope images suggested that its intense brightness was due to its exceptionally large size. While the nuclei of most comets are about 1.6 to 3.2 km (1 to 2 miles) across, Hale-Bopp's was estimated to be 40 km (25 miles) across. It was visible even through bright city skies, and may have been the most viewed comet in recorded history. Comet Hale-Bopp holds the record for the longest period of naked-eye visibility: an astonishing 19 months. It will not appear again for another 2,400 years. COMET SWIFT-TUTTLE 1992 COMET HALE-BOPP This comet was first seen in July 1862 by American astronomers Lewis Swift and Horace Tuttle. As Comet Swift-Tuttle moves closer to the Sun every 120 years, it leaves behind a trail of dust debris that provides the ingredients for a spectacular fireworks display seen in July and August. As Earth passes through the remnants of this dust tail, we can see on a clear night the Perseid meteor shower. Comet Swift-Tuttle is noted as the comet some scientists predicted could one day collide with Earth because the two orbits closely intercept each other. The latest calculations show that it will pass a comfortable 24 million km (15 million miles) from Earth on its next trip to the inner Solar System. COMET HYAKUTAKE On January 30, 1996, Yuji Hyakutake (pronounced "hyah-koo-tah-kay"), an amateur astronomer from southern Japan, discovered a new comet using a pair of binoculars. In the spring of that year this small bright comet with 1 of 3 1/23/2011 4:46 PM Famous Comets! 2 of 3 http://amazing-space.stsci.edu/resources/explorations/comets/lesson/facts... a nucleus of 1.6 to 3.2 km (1 to 2 miles) made a close flyby of Earth — sporting one of the longest tails ever observed. The Hubble Space Telescope studied the nucleus of this comet in great detail. This is not Comet Hyakutake's first visit to the inner Solar System. Astronomers have calculated its orbit and believe it was here about 8,000 years ago. Its orbit will not bring it near the Sun again for about 14,000 years. COMET HALLEY Comet Halley is perhaps the most famous comet in history. It was named after British astronomer Edmund Halley, who calculated its orbit. He determined that the comets seen in 1531 and 1607 were the same objects that followed a 76-year orbit. Unfortunately, Halley died in 1742, never living to see his prediction come true when the comet returned on Christmas Eve in 1758. Each time this comet's orbit approaches the Sun, its 15-km (9-mile) nucleus sheds about 6 m (7 yards) of ice and rock into space. This debris forms an orbiting trail that, when falling to Earth, is called the Orionids meteor shower. Comet Halley will return to the inner Solar System in the year 2061. COMET SHOEMAKER-LEVY 9 Between July 16 and July 22, 1994, more than 20 fragments of Comet Shoemaker-Levy 9 collided with the planet Jupiter. Astronomers Carolyn and Eugene Shoemaker and David Levy discovered the comet in 1993. The Hubble Space Telescope took many spectacular pictures of this event as the comet's pieces crashed into Jupiter's southern hemisphere. It was the first collision of two Solar System bodies ever to be recorded. The impacts created atmospheric plumes many thousands of kilometers high that showed hot "bubbles" of gas with large dark "scars" covering the planet's sky. 1/23/2011 4:46 PM Amazing Space- Fast Facts: Comet Hale-Bopp 1 of 2 Homepage Celebrating Hubble's 20th Anniversary http://amazing-space.stsci.edu/resources/fastfacts/comet-halebopp.php.p... Capture the cosmos > Comets > Dig deeper (cont'd) > Fast Facts: Comet Hale-Bopp Description The Star Witness news Hale-Bopp has a very large nucleus. (Most comet nuclei measure only 1.6 to 3.2 km, or 1-2 miles, in diameter.) It could be seen in the sky for a record 19 months — from May 1996 to November 1997 — and was visible through the bright skies of cities. Age About the same age as the Sun: 4.5 billion years Capture the cosmos Location Outer solar system — Oort Cloud Avg. distance from the Sun It has a highly elongated orbit that takes it very close to the Sun and then flings it out into the outer solar system, well past the orbit of Pluto. Diameter The diameter of the nucleus has been estimated to be 40-80 km (25-50 miles). Mass Not determined Orbital period around the Sun 2,392 Earth years Hubble's Servicing Mission 4 Online explorations Astronomy materials, by topic Tonight's Sky Homework help (Image courtesy of Alessandro Dimai) Capture the cosmos > Comets > Dig deeper (cont'd) > Fast Facts: Comet Hale-Bopp 1/23/2011 4:51 PM Comet Hale-Bopp - Bob the Alien's Tour of the Solar System 1 of 2 HOME THE SOLAR SYSTEM COMETS What are Comets? Halley's Comet Comet Hale-Bopp Shoemaker-Levy Halley's Comet Facts STARS & GALAXIES ASTEROIDS ASTRONOMY SPACE EXPLORATION SPACE A-Z ASK AN ALIEN! SPACE QUIZ USEFUL RESOURCES SITE MAP What are Comets? Shoemaker-Levy Comet Halley's Comet http://www.bobthealien.co.uk/cometshalebopp.htm Comet Hale-Bopp Ten Facts About Halley's Comet The view of the night sky from Earth is very familiar. On a clear night, you know that you will be able to look into the sky and see the Moon and lots of stars. Sometimes though, the Moon and stars are joined by other objects. If you looked into the sky on an evening early in 1997, you may have been able to see what looked like a star which had been smudged. In fact, this smudged star was a comet, one of the brightest comets visible from Earth for many years. It was named Comet Hale-Bopp and remained visible from Earth for 19 months, being at its brightest and clearest during the first half of 1997. Comets are balls of ice, dust and gas which travel in elliptical orbits around the Sun. At their most distant, they are invisible. However, when they get closer to the Sun, they begin glowing, forming a coma and tails as dust and gas is burnt off the comet. It is only when they have begun glowing that they become visible from Earth with telescopes. This means that they usually only get discovered two or three months before they actually get close to Earth. However, Hale-Bopp was different. it was discovered almost two years before it became a prominent feature in the night sky. What is Quantum Jumping? Discover Why Thousands of People are "Jumping" to Change Their Life www.QuantumJumping.c Car Insurance - $15 Month Get Super Cheap Car It was a summer's evening in July 1995 when two astronomers in different parts of America happened to be observing the Insurance for Low Income Drivers - $15 / same part of the sky. Alan Hale is a professional astronomer and was working at his observatory in New Mexico on the Month! evening of 22nd July. He was actually observing other comets, but while waiting for one previously discovered comet to come Low-Income-Car-Insuranc into view, he turned his telescope to a group of stars called M70 (a globular cluster). At a similar time, Tom Bopp, an amateur astronomer at a "star party" in Phoenix (a gathering for astronomers to observe the stars together!), was also observing the M70 globular cluster. Both astronomers noticed a small fuzzy object in a place where there shouldn't be a fuzzy object. Alan Hale suspected the object may be a comet, but had to check it hadn't already been discovered. He referred to his big comet catalogue and noticing it wasn't in there, he emailed the Central Bureau for Astronomical Telegrams. He returned to his discovery and noticed that the object had moved against the starry backdrop, confirming that it definitely was a comet. He then sent a second email. When Tom Bopp observed the object, he called over some friends. They watched the object move against the stars in the background and, realising he had discovered a comet, Bopp also got in touch with the Central Bureau for Astronomical Telegrams to inform them of this. Because both people discovered the comet at about the same time, it was named after both of them, hence the name Comet Hale-Bopp. When the comet was discovered, it was about as far away from Earth as Jupiter is. The comet doesn't orbit on the same path as the planets. In the diagram to the left, the orbits of the four inner planets and Jupiter can be seen. The path that Hale Bopp takes can also be seen.. Because Hale-Bopp was discovered when it was so far away from Earth, there was a great deal of anticipation that when it got closer, it would be very bright. Halley's Comet, which last visited in 1986, has a nucleus of 20km. The nucleus of Hale Bopp is 40km, much larger than most comets. After discovery, the comet continued on its journey towards the Sun. As it got closer, its tail got larger and became easier to spot. On 20th May 1996, Terry Lovejoy of Queensland, Australia became the first person to spot the comet with the naked eye. It would have still been very faint from Earth, but as the months went on, more and more people reported sightings of the comet without the assistance of a telescope or binoculars. Throughout the summer of 1996, Comet Hale-Bopp actually became dimmer, leading scientists to believe that it had fizzled out. However, it began getting brighter again and in early 1997, it was clearly visible from Earth. The comet came closest to Earth on 22nd March 1997 (at a distance of over 122 million kilometres) and closest to the Sun on 1st April 1997. After reaching the Sun and going behind it the comet was thrown back out and continued its journey away from the Sun, becoming less and less visible from Earth. It is estimated that it will return in 2,300 years, in the year 4534! The comet would have last been visible 4,200 years ago. The reason its next visit is sooner than its last visit is because in March 1997, Comet Hale-Bopp passed within the gravitational influence of Jupiter, shortening the length of time it takes to complete an orbit. The furthest the comet will go from the Sun now is 371 AU (Astronomical Units). 1 AU is approximately the distance Earth is from the Sun, so Hale-Bopp will go 371 times as far 1/23/2011 4:59 PM Comet Hale-Bopp - Bob the Alien's Tour of the Solar System 2 of 2 http://www.bobthealien.co.uk/cometshalebopp.htm from the Sun as Earth is. Comet Hale-Bopp spent four months as a regular clear object in the night sky. it is estimated that 81% of Americans saw it, and the comet became the most photographed comet in the history of, er, comet photography. I suppose this isn't such a great claim when you realise that the last great comet was in 1811 before cameras were even invented! The comet was visible from Earth with the naked eye for a record breaking 19 months. The comet was very much a comet of the Internet Boom of the late 1990s. The fast increase in Internet users meant that people all over the world could share information about sightings, pictures, etc. with each other. The original Comet Hale-Bopp website became NASA's first website to achieve 1 million hits in one day. If only this website was around back then - it might have had a visit or two! Comet Hale-Bopp also had a darker side. Throughout history, comets have been seen as omens; a sign that something was going to happen. An early image of the comet was taken by an amateur astronomer which showed a mysterious object which looked like it was following the comet. This object didn't match up with any stars that should have been in the area, so the astronomer contacted a radio show stating that Hale-Bopp was being accompanied by a Saturn-Like Object. A cult calling themselves Heaven's Gate believed that this Saturn-like object could be a UFO. 39 members of the cult killed themselves, believing that their spirits would be taken to another world by this UFO. That's what happens when you watch too much X-Files! Analysis of the image proved that the object was in fact a star. For most of us, Comet Hale-Bopp was simply a once-in-a lifetime opportunity to see a comet. It is now hundreds of millions of miles away from us and has much further to go before it even starts to return to our part of the Solar System. Of course, there may be other comets about to visit us, and some may be even brighter than Hale-Bopp. Comets are mysterious objects. Unless they have been previously discovered and visit regularly (like Halley's Comet), we don't know they exist until they get very close to us. And even when they have been discovered, it isn't until they get even closer that we find out just how spectacular it is. HaleBobStore.com Ads by Google What are Comets? Shoemaker-Levy Comet Halley's Comet Comet Hale-Bopp Ten Facts About Halley's Comet Translate Web © 2010 www.bobthealien.co.uk Gadgets powered by Google Home | Contact Bob | Privacy Policy | About This Site | Site Map 1/23/2011 4:59 PM How Comet Hyakutake B2 Was Discovered 1 of 2 http://www2.jpl.nasa.gov/comet/hyakutake/disc2.html March 29, 1996 I am a 45-year old amateur astronomer from Kagoshima, Japan. My name, Hyakutake, means "100 samurai, or chivalry," in Japanese. It is not a very common name in Japan. I graduated from the Art Department at Kyushu Industry University, where I majored in photography. I live in the village of Hayato, in the southernmost prefecture located 600 miles southwest of Tokyo on the island of Kyushu. I lived in Fukuoka for many years, but moved to Kagoshima because the skies are much clearer there. I have been married for 15 years, and have two sons, ages 10 and 13. I am the only one in my family whose hobby is searching for comets. My younger son likes the television show, "The X-Files." I've been interested in comets since I was 15 years old, after I heard of the Japanese Comet Ikeya-Seki which appeared in 1965. My interest in astronomy has increased steadily since then. I wanted to discover a comet that had a very far orbit. Although I started searching for comets about seven years ago when I lived in Fukuoka, I have concentrated my efforts more intensely since I moved to Kagoshima two years ago. Since last July, I have been avidly searching the night sky for comets from 2 a.m. to 5 a.m., about four nights a month. I want to continue searching for comets while my eyesight is reasonably good. Many people have asked me how I discovered Comet Hyakutake. I live in the countryside and travel to a rural mountain top area about 10 miles from my home to get a better view of the night sky. (Before I was married, I enjoyed mountain climbing.) Actually, I discovered two comets. I spotted the first one at 5:40 a.m. on December 26. I wasn't sure it was a comet, but I reported the sighting anyway. This first comet is still there, but it's not very bright. A month later, I went back to the area to take photos of the first comet. I looked l up at the sky where it should have been at that point in its path. However, that particular spot was filled with clouds. I tried to find an area in the sky that was unobscured. The clouds led me back to the same spot in the sky where I had originally found the first comet, but it didn't make sense that it would be there. That is when I discovered the second Comet Hyakutake, the one the media now refers to as "The Comet of the Century." I've been asked about 75 times how I felt when I discovered this comet. Actually, I was feeling a bit confused. My reaction was somewhat complicated, since I had originally intended to go to the viewing spot to take a picture of my first comet. I found the second comet in the same area as the first one, near the constellations of Libra and Hydra. 1/23/2011 5:03 PM How Comet Hyakutake B2 Was Discovered 2 of 2 http://www2.jpl.nasa.gov/comet/hyakutake/disc2.html I discovered Comet Hyakutake at 4:50 in the morning, and usually a person can report a comet after 8 a.m., but I decided to take some photos of the comet, using my camera with telephoto lenses, and got them developed. It wasn't until 11 a.m. that I called the National Astronomy Observatory in Tokyo to report my new comet. I followed the formal procedure of gathering data and documenting my new comet discovery with photos. Then two other amateur astronomers in Japan recognized the comet. It's interesting that my discovery wasn't reported very widely by the Japanese media until recently. The first media reports were from London. Then the American press became very interested. Now the Japanese media is covering the comet story. My wife can't make phone calls because the phone is always ringing. I'm happy that this Comet Hyakutake was the second one I discovered, because it wasn't mere coincidence. This proved to me that my method of searching for comets is working, and I will continue to look for them. I use high-powered, field binoculars with 6-inch lenses, mounted on a stand. This is the only equipment I own. Comet Hyakutake has the longest tail that I have ever observed, although the new Hubble images show that this comet is breaking into fragments. I am a bit perplexed by all the attention paid to me, when it is the comet that deserves the credit. Comet 1996 B2 Hyakutake Home Page 1/23/2011 5:03 PM Comet Hyakutake - Wikipedia, the free encyclopedia 1 of 7 http://en.wikipedia.org/wiki/Comet_Hyakutake From Wikipedia, the free encyclopedia C/1996 B2 (Hyakutake) Comet Hyakutake (Japanese pronunciation: [çʲakɯ̥take], formally designated C/1996 B2) is a comet, discovered on January 31, 1996,[1] which passed very close to Earth in March of that year. It was dubbed The Great Comet of 1996; its passage near the Earth was one of the closest cometary approaches of the previous 200 years. Hyakutake appeared very bright in the night sky and was widely seen around the world. The comet temporarily upstaged the much anticipated Comet Hale-Bopp, which was approaching the inner Solar System at the time. Scientific observations of the comet led to several discoveries. Most surprising to cometary scientists was the first discovery of X-ray emission from a comet, believed to have been caused by ionised solar wind particles interacting with neutral atoms in the coma of the comet. The Ulysses spacecraft unexpectedly crossed the comet's tail at a distance of more than 500 million km from the nucleus, showing that Hyakutake had the longest tail known for a comet. Hyakutake is a long-period comet. Before its most recent passage through the Solar System, its orbital period was about 17,000 years, but the gravitational influence of the giant planets has increased this period to 72,000 years. 1 Discovery 2 Orbit 3 The comet passes the Earth 4 Perihelion and afterwards 5 Scientific results 5.1 Spacecraft passes through the tail 5.2 Composition 5.3 X-ray emission 5.4 Nucleus size and activity Comet Hyakutake captured by the Hubble Space Telescope on April 4, 1996, with an infrared filter. Discovery and designation Discovered by Yuji Hyakutake Discovery date 31 January 1996[1] Designations Great Comet of 1996 Alternate name(s)[note 1] Orbital characteristics[2] Epoch 2450400.5 Ap Peri Semi-major axis Eccentricity Orbital period Inclination Longitude of ascending node Argument of peri 4367.87 AU 0.2301987 AU 2184.05 AU 0.9998946 102070 a 124.92246° 188.05766° 130.17218° Physical characteristics Dimensions Sidereal rotation period Absolute magnitude (H) 4.2 km[3] 6 hours ~5.3 1. ^ Minor Planet Designations (http://cfa-www.harvard.edu /iau/MPDes.html) 6 References 7 External links 1/23/2011 5:06 PM Comet Hyakutake - Wikipedia, the free encyclopedia 2 of 7 http://en.wikipedia.org/wiki/Comet_Hyakutake The comet was discovered on January 31, 1996,[1] by Yuji Hyakutake, an amateur astronomer from southern Japan.[4] He had been searching for comets for years and had moved to Kagoshima Prefecture partly for the dark skies in nearby rural areas. He was using a powerful set of binoculars with 150 mm (6 inch) objective lenses to scan the skies on the night of the discovery.[5] This comet was actually the second Comet Hyakutake; Hyakutake had discovered comet C/1995 Y1 several weeks earlier.[6] While re-observing his first comet (which never became visible to the naked eye) and the surrounding patch of sky, Hyakutake was surprised to find another comet in almost the same position as the first had been. Hardly believing a second discovery so soon after the first, Hyakutake reported his observation to the National Astronomical Observatory of Japan the following morning.[7] Later that day, the discovery was confirmed by independent observations. At the time of its discovery, the comet was shining at magnitude 11.0 and had a coma approximately 2.5 arcminutes across. It was approximately 2 astronomical units (AU) from the Sun.[8] Later, a pre-discovery image of the comet was found on a photograph taken on January 1, when the comet was about 2.4 AU from the Sun and had a magnitude of 13.3.[9] When the first calculations of the comet's orbit were made, scientists realized that it was going to pass just 0.1 AU from the Earth on 25 March.[10] Only four comets in the previous century had passed closer.[11] Comet Hale-Bopp was already being discussed as a possible "great comet"; the astronomical community eventually realised that Hyakutake might also become spectacular because of its close approach. Moreover, the comet's orbit showed that it had last returned to the inner Solar System approximately 17,000 years earlier. Because the comet had probably passed close to the Sun several times before,[9] the approach in 1996 would not be a maiden arrival from the Oort cloud, a place where comets with orbital periods of millions of years come from. Comets entering the inner Solar System for the first time may brighten rapidly before fading as they near the Sun, as a layer of highly volatile material evaporates. This was the case with Comet Kohoutek in 1973; it was initially touted as potentially spectacular, but only appeared moderately bright. Older comets show a more consistent brightening pattern. Thus, all indications pointed that Comet Hyakutake would be bright. Besides approaching close to the Earth, the comet would also be visible throughout the night to northern hemisphere observers at its closest approach because of its path, passing very close to the pole star. This would be an unusual occurrence, because most comets are close to the Sun in the sky when the comets are at their brightest, leading to the comets appearing in a sky not completely dark. 1/23/2011 5:06 PM Comet Hyakutake - Wikipedia, the free encyclopedia 3 of 7 http://en.wikipedia.org/wiki/Comet_Hyakutake Hyakutake became visible to the naked eye in early March 1996. By mid-March, the comet was still fairly unremarkable, shining at 4th magnitude with a tail about 5 degrees long. As it neared its closest approach to Earth, it rapidly became brighter, and its tail grew in length. By March 24, the comet was one of the brightest objects in the night sky, and its tail stretched 35 degrees. The comet had a notably bluish-green colour.[9] The closest approach occurred on 25 March. Hyakutake was moving so rapidly across the night sky that its movement could be detected against the stars in just a few minutes; it covered the The comet on the evening of its closest diameter of a full moon (half a degree) every 30 minutes. Observers approach to Earth on 25 March 1996. estimated its magnitude as around 0, and tail lengths of up to 80 degrees were reported.[9] Its coma, now close to the zenith for observers at mid-northern latitudes, appeared approximately 1.5 to 2 degrees across, roughly four times the diameter of the full moon.[9] Even to the naked eye, the comet's head appeared distinctly green, due to strong emissions from diatomic carbon (C2). Because Hyakutake was at its brightest for only a few days, it did not have time to permeate the public imagination in the way that Comet Hale-Bopp did the following year. Many European observers in particular did not see the comet at its peak because of unfavourable weather conditions.[9] After its close approach to the Earth, the comet faded to about 2nd magnitude. It reached perihelion on May 1, 1996, brightening again and exhibiting a dust tail in addition to the gas tail seen as it passed the Earth. By this time, however, it was close to the Sun and was not seen as easily. It was observed passing perihelion by the SOHO Sun-observing satellite, which also recorded a large coronal mass ejection being formed at the same time. Its distance from the Sun at perihelion was 0.23 AU, well inside the orbit of Mercury.[12] After its perihelion passage, Hyakutake faded rapidly and was lost to naked-eye visibility by the end of May. Its orbital path carried it rapidly into the southern skies, but following perihelion it became much less monitored. The last known observation of the comet took place on November 2.[13] Hyakutake had passed through the inner Solar System approximately 17,000 years ago; gravitational interactions with the gas giants during its 1996 passage stretched its orbit greatly, and fits to the comet's orbit predicted it will not return to the inner Solar System again for approximately 72,000[9] to 114,000 years.[14] The SOHO satellite captured this image of Hyakutake as it passed perihelion, with a nascent coronal mass ejection also visible to the left of the Sun. Spacecraft passes through the tail 1/23/2011 5:06 PM 4 of 7 The Ulysses spacecraft made an unexpected pass through the tail of the comet on May 1, 1996.[15] Evidence of the encounter was not noticed until 1998. Astronomers analysing old data found that Ulysses' instruments had detected a large drop in the number of protons passing, as well as a change in the direction and strength of the local magnetic field. This implied that the spacecraft had crossed the 'wake' of an object, most likely a comet; the object responsible was not immediately identified. In 2000, two teams independently analyzed the same event. The magnetometer team realized that the changes in the direction of the magnetic field mentioned above agreed with the "draping" pattern expected in a comet's ion, or plasma tail. The magnetometer team looked for likely suspects. No known comets were located near the satellite, but looking further afield, they found that Hyakutake, 500 million km away, had crossed Ulysses' orbital plane on April 23, 1996. The solar wind had a velocity at the time of about 750 km/s, at which speed it would have taken eight days for the tail to be carried out to where the spacecraft was situated at 3.73 AU, approximately 45 degrees out of the ecliptic plane. The orientation of the ion tail inferred from the magnetic field measurements agreed with the source lying in Comet Hyakutake's orbital plane.[16] The other team, working on data from the spacecraft's ion composition spectrometer, discovered a sudden large spike in detected levels of ionised particles at the same time. The relative abundance of chemical elements detected indicated that the object responsible was definitely a comet.[17] Based on the Ulysses encounter, the comet's tail is known to have been at least 570 million km (360 million miles; 3.8 AU) long. This is almost twice as long as the previous longest-known cometary tail, that of the Great Comet of 1843, which was 2.2 AU long. Composition Terrestrial observers found ethane and methane in the comet, the first time either of these gases had been detected in a comet. Chemical analysis showed that the abundances of ethane and methane were roughly equal, which may imply that its ices formed in interstellar space, away from the Sun, which would have evaporated these volatile molecules. Hyakutake's ices must have formed at temperatures of 20 K or less, indicating that it probably formed in a denser than average interstellar cloud.[18] The amount of deuterium in the comet's water ices was determined through spectroscopic observations.[19] It was found that the ratio of deuterium to hydrogen (known as the D/H ratio) was about 3 × 10−4, which compares to a value in Earth's oceans of about 1.5 × 10−4. It has been proposed that cometary collisions with Earth might have supplied a large proportion of the water in the oceans, but the high D/H ratio measured in Hyakutake and other comets such as Hale-Bopp and Halley's Comet have caused problems for this theory. 1/23/2011 5:06 PM Amazing Space- Fast Facts: Comet Halley 1 of 2 Homepage for educators and developers http://amazing-space.stsci.edu/resources/fastfacts/comet-halley.php.p=Tea... Teaching tools > Comets > Overview: Comet Halley facts > Fast Facts: Comet Halley Teaching tools Astronomy basics Description Halley is perhaps the most famous comet in history. This is the comet that proved correct Edmund Halley's prediction that it would reappear. It is responsible for depositing the debris that, when falling through Earth's atmosphere, causes the Orionid meteor showers. Age About the same age as the Sun: 4.5 billion years Location Outer solar system — Kuiper belt Avg. distance from the Sun It has a highly elongated orbit that takes it very close to the Sun and then flings it out into the outer solar system, well past the orbit of Pluto. Diameter The size of the nucleus has been estimated to be 15 km x 7 km x 7 km (or 9 mi x 4 mi x 4 mi). Mass 1.7 x 1015 kilograms Orbital period around the Sun 76 Earth years E/PO resources (Image courtesy of NASA) Teaching tools > Comets > Overview: Comet Halley facts > Fast Facts: Comet Halley 1/23/2011 5:47 PM Comet Halley 1 of 2 http://www.solarviews.com/eng/halley.htm Custom Search Home | Site Map | What's New | Image Index | Copyright | Puzzles | Posters | ScienceViews | Spacecraft that have visited Halley's Comet Halley's [HAL-lee] Comet has been know since at least 240 BC and possibly since 1059 BC. Its most famous appearance was in 1066 AD when it was seen right before the Battle of Hastings. It was named after Edmund Halley, who calculated its orbit. He determined that the comets seen in 1531 and 1607 were the same object that followed a 76-year orbit. Unfortunately, Halley died in 1742, never living to see his prediction come true when the comet returned on Christmas Eve 1758. Halley's Comet put on bright shows in 1835 and in 1910. Then in 1984 and 1985, five spacecraft from the USSR, Japan and Europe were launched to make a rendezvous with Halley's Comet in 1986. One of NASA's deep space satellites was redirected to monitor the solar wind upstream from Halley. Only three comets have ever been studied by spacecraft. Comet Giacobini-Zinner was studied in 1985, Comet Halley in 1986, and CometGriggSkjellerup on July 10th, 1992. The nucleus of Halley is ellipsoidal in shape and measures approximately 16 by 8 by 8 kilometers (10 by 5 by 5 miles). Halley's Comet Statistics Perihelion distance: 0.587 AU Orbital eccentricity: 0.967 Orbital inclination: 162.24° Orbital period: 76.0 years Next perihelion: 2061 Diameter: 16 x 8 x 8 km Animation of Halley's Comet Animation of Halley's comet from Giotto pictures. (Courtesy A.Tayfun Oner) Views of Halley's Comet Comet Halley in False Color This image of Halley's Comets was taken during its 1986 appearance. False-color digital enhancement was used to permit measurement of slight brightness differences. (Copyright Calvin J. Hamilton) Giotto Mosaic of Halley's Comet This image is a mosaic of 8 images taken by the Giotto spacecraft during the Halley encounter on March 13, 1/23/2011 5:16 PM Halley's comet 1 of 3 http://www.windows2universe.org/comets/Halleys_comet.html Brought to you by the National Earth Science Teachers Association This image of the nucleus of Halley's comet comes from the Giotto spacecraft. Click on image for full size JPL Halley's comet Halley's comet is named after Edmond G. Halley who was the first to suggest that comets were natural phenomena of the solar system, in orbit around the Sun. He suggested that a certain comet was a regular visitor, returning every 76 years, and was, in fact, the same one which had been observed since 240 BC, but in particular in the years 1531, 1607, and 1682, dates which for him were recent history. In 1682 he predicted the comet would return again in 1758, and sure enough, the comet arrived in March 1759. Halley's comet made a particularly bright appearance in 1910. It also was recorded in a famous ancient tapestry after its 1066 appearance. For hundreds of years humankind has wondered what the nucleus of Halley's comet was really like. This wonderful picture from the Giotto spacecraft gives us the answer. In this picture, the Sun is on the left. Three jets can be seen blowing molecules toward the Sun. A crater can also be seen in the middle right. This image shows that evaporation occurs along specific portions of the comet. Data taken by a suite of spacecraft suggests that the comet is mostly made of ice. Halley's comet is next scheduled to return in 2062. Last modified December 6, 2000 by Jennifer Bergman. News Flash! 1/23/2011 5:17 PM Comet West - Wikipedia, the free encyclopedia 1 of 2 http://en.wikipedia.org/wiki/Comet_West From Wikipedia, the free encyclopedia There is another long-period comet West: C/1978 A1 (a.k.a. 1977 IX, 1978a). Comet West formally designated C/1975 V1, 1976 VI, and 1975n, was a spectacular comet, sometimes considered to qualify for the status of "great comet". C/1975 V1 (West) 1 Discovery 2 Breakup 3 Nomenclature 4 References It was discovered photographically by Richard M. West, of the European Southern Observatory, on August 10, 1975, and reached peak brightness in March 1976, attaining a brightness of -3 at perihelion. During peak brightness, observers reported that it was bright enough to study during full daylight. Despite its spectacular appearance, Comet West went largely unreported in the popular media. This was partly due to the relatively disappointing display of Comet Kohoutek in 1973, which had been widely predicted to become extremely prominent: scientists were wary of making predictions that might raise public expectations.[1] Discovery Discovered by: Richard M. West Discovery date: August 10, 1975 Alternate C/1975 V1, 1976 VI, designations: 1975n Orbital characteristics A (http://www.minorplanetcenter.org/iau/Ephemerides /Comets/) Epoch: Aphelion distance: Perihelion distance: Semi-major axis: Eccentricity: Orbital period: Inclination: Last perihelion: 2442840.5 13560 AU 0.58 AU 6,780.20 AU 0.99997 558,306.4201 a 43.0664° February 25, 1976 The comet has an estimated orbital period of 558,000 years. During the passage of Comet West into the inner solar system, possibly for the first time in 500,000 years, its nucleus was observed to split into four fragments as it passed within 30 million km of the Sun. The first report of the split came around 7 March 1976 12:30UT, when reports were received that the comet had broken into two pieces. Astronomer Steven O'Meara, using the 9-inch Harvard Refractor, reported that two additional fragments had formed on the morning of 18 March. The fragmentation of the nucleus was, at the time, one of very few comet breakups observed, one of the most notable previous examples being the Great Comet of 1882, a member of the Kreutz Sungrazing 'family' of comets. More recently, comets Schwassmann-Wachmann-3 (73/P), C/1999 S4 LINEAR, and 57/P du Toit-Neujmin-Delporte, have been observed to disintegrate during their passage close to the Sun. 1/23/2011 5:35 PM Comet Encke - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Comet_Encke From Wikipedia, the free encyclopedia 2P/Encke Comet Encke or Encke's Comet (official designation: 2P/Encke) is a periodic comet that completes an orbit of the sun once every three years — the shortest period of any known comet. It was first recorded by Pierre Méchain in 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke; like Halley's Comet, it is unusual in being named after the calculator of its orbit rather than its discoverer. 1 Discovery 2 Characteristics 3 Observations 4 Meteor showers 5 Effects on Earth 6 Importance in the scientific history of luminiferous aether 7 See also 8 References 9 External links Discovered by: Discovery date: Alternate designations: Discovery Pierre Méchain 1786 1786 I; 1795; 1805; 1819 I; 1822 II; 1825 III; 1829; 1832 I; 1835 II; 1838; 1842 I; 1845 IV Orbital characteristics A (http://www.minorplanetcenter.org/iau/Ephemerides /Comets/) As its official designation implies, Encke's Comet was the first periodic comet discovered after Halley's Comet (designated 1P/Halley). Its orbit was calculated by Johann Franz Encke, who, through laborious calculations was able to link observations of comets in 1786 (designated 2P/1786 B1), 1795 (2P/1795 V1), 1805 (2P/1805 U1) and 1818 (2P/1818 W1) to the same object. In 1819 he published his conclusions in the journal Correspondance astronomique, and predicted correctly its return in 1822 (2P/1822 L1). September 22, 2006 (JD 2454000.5) Aphelion distance: 4.11 AU Perihelion distance: 0.3302 AU Semi-major axis: 2.2178 AU Eccentricity: 0.8471 Orbital period: 3.30 a Inclination: 11.76° Last perihelion: 6 August 2010[1] Epoch: Next perihelion: 21 November 2013[1] The diameter of the nucleus of Encke's Comet is 4.8 km.[2] Comets are in unstable orbits that evolve over time due to perturbations and outgassing. Given Encke's low orbital inclination near the ecliptic and brief orbital period of 3 years, the orbit of Encke is frequently perturbed by the inner planets.[3] 1 of 4 1/23/2011 5:38 PM The failed CONTOUR mission was launched to study this comet, and also Schwassmann-Wachmann 3. On April 20, 2007, the tail of Comet Encke was observed to be temporarily torn off by magnetic field disturbances caused by a Coronal Mass Ejection: a blast of solar particles from the sun.[4] The tail grew back due to the continuous shedding of dust and gas by the comet.[5] Comet Encke is believed to be the originator of several related meteor showers known as the Taurids (which are encountered as the Northern and Southern Taurids across November, and the Beta Taurids in late June and early July).[6][7] Near-Earth object 2004 TG10 may be a fragment of Encke.[8] More than one theory has associated Encke's Comet with impacts of cometary material on Earth, and with cultural significance. A Spitzer image of Encke and its debris trail in infrared light. Credit: (NASA/JPL-Caltech/University of Minnesota) The Tunguska event of 1908, probably caused by the impact of a cometary body, has also been postulated by Czechoslovakian astronomer Ľubor Kresák as a fragment of Comet Encke.[9] A theory holds that the ancient symbol of the swastika appeared in a variety of cultures across the world at a similar time, and could have been inspired by the appearance of a comet from head on, as the curved jets would be reminiscent of the swastika shape (see Comets and the swastika motif). Comet Encke has sometimes been identified as the comet in question. In their 1982 book Cosmic A Han Dynasty silk comet atlas, featuring drawings of Serpent (page 155) Victor Clube and Bill Napier comets believed by Victor Clube and Bill Napier to be reproduce an ancient Chinese catalogue of cometary related to the breakup of Encke's Comet in the past shapes from the Mawangdui Silk Texts, which includes a swastika-shaped comet, and suggest that some of the comet drawings were related to the breakup of the progenitor of Encke and the Taurid meteoroid stream. Fred Whipple in his The Mystery of Comets (1985, page 163) points out that Comet Encke's polar axis is only 5 degrees from its orbital plane: such an orientation is ideal to have presented a pinwheel like aspect to our ancestors when Encke was more active. Comet 73P/Schwassmann-Wachmann 3 1 of 4 http://www.solarviews.com/eng/wachmann.htm Contents | What's New | Image Index | Copyright | Puzzles | Posters | Search | Table of Contents Comet Introduction Comet Historical Background Comets Comet 73P/Schwassmann Wachmann 3 Comet Borrelly Halley's Comet Shoemaker-Levy 9 Shoemaker-Levy 9 Background Shoemaker-Levy 9 Impact Hubble PR - Collision Results Comet LINEAR Comet P/Wild-2 Comet Tempel 1 Deep Impact Crash into Comet Tempel 1 Deep Impact Tells a Tale of the Comet Comet Information Hale-Bopp Fails Emission Tests but Reveals Comet Origin Kuiper Belt Objects Comets Beyond Neptune Comet Tutorial Make a Comet Nucleus Comet Space Exploration Chronology Comet Image/Animation Gallery NASA's Hubble Space Telescope is providing astronomers with extraordinary views of comet 73P/SchwassmannWachmann 3, which is falling apart right before our eyes. Recent Hubble images have uncovered many more fragments than have been reported by ground-based observers. These observations provide an unprecedented opportunity to study the demise of a comet nucleus. Amateur and professional astronomers around the world have been tracking for years the spectacular disintegration of 73P/Schwassmann-Wachmann 3. As it plunges toward a June 6th swing around the Sun, the comet will pass Earth on May 12th, at a distance of 7.3 million miles, or 30 times the distance between Earth and the Moon. The comet is currently comprised of a chain of over three dozen separate fragments, named alphabetically, stretching across several degrees on the sky. (The Sun and Moon each have an apparent diameter of about 1/2 of a degree.) Ground-based observers have noted dramatic brightening events associated with some of the fragments (as shown in the bottom frame) indicating that they are continuing to break-up and that some may disappear altogether. Hubble caught two of the fragments, B and G, (top frames) shortly after large outbursts in activity. Hubble also photographed fragment C (not shown), which was less active. The resulting images reveal that a hierarchical destruction process is taking place, in which fragments are continuing to break into smaller chunks. Several dozen "mini-fragments" are found trailing behind each main fragment, probably associated with the ejection of house-sized chunks of surface material that can only be detected in these very sensitive and high-resolution Hubble images. 1/23/2011 5:41 PM Comet 73P/Schwassmann-Wachmann 3 2 of 4 http://www.solarviews.com/eng/wachmann.htm Sequential Hubble images of the B fragment, taken a few days apart, suggest that the chunks are pushed down the tail by outgassing from the icy, sunward-facing surfaces of the chunks, much like space-walking astronauts are propelled by their jetpacks. The smaller chunks have the lowest mass, and so are accelerated away from the parent nucleus faster than the larger chunks. Some of the chunks seem to dissipate completely over the course of several days. Deep-freeze relics of the early solar system, cometary nuclei are porous and fragile mixes of dust and ices. They can be broken apart by gravitational tidal forces when they pass near large bodies (for example, Comet Shoemaker-Levy 9 was torn to pieces when it skirted near Jupiter in 1992, prior to plunging into Jupiter's atmosphere two years later). They can also fly apart from rapid rotation of the nucleus, break apart because of thermal stresses as they pass near the Sun, or explosively pop apart like corks from champagne bottles due to the outburst of trapped volatile gases. "Catastrophic breakups may be the ultimate fate of most comets," says planetary astronomer Hal Weaver of the Johns Hopkins University Applied Physics Laboratory, who led the team that made the recent Hubble observations and who used Hubble previously to study the fragmentations of comets Shoemaker-Levy 9 in 1993-1994, Hyakutake in 1996, and 1999 S4 (LINEAR) in 2000. Analysis of the new Hubble data, and data taken by other observatories as the comet approaches the Earth and Sun, may reveal which of these breakup mechanisms are contributing to the disintegration of 73P/Schwassmann-Wachmann 3. German astronomers Arnold Schwassmann and Arno Arthur Wachmann discovered this comet during a photographic search for asteroids in 1930, when the comet passed within 5.8 million miles of the Earth (only 24 times the Earth-Moon distance). The comet orbits the Sun every 5.4 years, but it was not seen again until 1979. The comet was missed again in 1985 but has been observed every return since then. During the fall of 1995, the comet had a huge outburst in activity and shortly afterwards four separate nuclei were identified and labeled "A", "B", "C", and "D", with "C" being the largest and the presumed principal remnant of the original nucleus. Only the C and B fragments were definitively observed during the next return, possibly because of the poor geometry for the 2000-2001 apparition. The much better observing circumstances during this year's return may be partly responsible for the detection of so many new fragments, but it is also likely that the disintegration of the comet is now accelerating. Whether any of the many fragments will survive the trip around the Sun remains to be seen. Besides Weaver, the other members of the Hubble observing team are: Carey Lisse (JHU/APL), Philippe Lamy (Laboratoire d'Astronomie Spatiale, France), Imre Toth (Hungarian Academy of Sciences), William Reach (IPAC/Caltech), and Max Mutchler (STScI). Z. Levay (STScI) Additional Image of Comet Borrelly A Million Comet Pieces This infrared image from NASA's Spitzer Space Telescope shows the broken Comet 73P/Schwassman-Wachmann 3 skimming along a trail of debris left during its multiple trips around the sun. The flame-like objects are the comet's fragments and their tails, while the dusty comet trail is the line bridging the fragments. Comet 73P /Schwassman-Wachmann 3 began to splinter apart in 1995 during one of its voyages around the sweltering sun. Since then, the comet has continued to disintegrate into dozens of fragments, at least 36 of which can be seen here. Astronomers believe the icy comet cracked due the thermal stress from the sun. The Spitzer image provides the best look yet at the trail of debris left in the comet's wake after its 1995 breakup. 1/23/2011 5:41 PM Comet 73P/Schwassmann-Wachmann 3 3 of 4 http://www.solarviews.com/eng/wachmann.htm The observatory's infrared eyes were able to see the dusty comet bits and pieces, which are warmed by sunlight and glow at infrared wavelengths. This comet debris ranges in size from pebbles to large boulders. When Earth passes near this rocky trail every year, the comet rubble burns up in our atmosphere, lighting up the sky in meteor showers. In 2022, Earth is expected to cross close to the comet's trail, producing a noticeable meteor shower. Astronomers are studying the Spitzer image for clues to the comet's composition and how it fell apart. Like NASA's Deep Impact experiment, in which a probe smashed into comet Tempel 1, the cracked Comet 73P/Schwassman-Wachmann 3 provides a perfect laboratory for studying the pristine interior of a comet. (Courtesy NASA/JPL-Caltech) Hubble Provides Spectacular Detail of a Comet's Breakup Hubble Space Telescope is providing astronomers with extraordinary views of Comet 73P/Schwassmann-Wachmann 3. The fragile comet is rapidly disintegrating as it approaches the Sun. Hubble images have uncovered many more fragments than have been reported by ground-based observers. These observations provide an unprecedented opportunity to study the demise of a comet nucleus. The comet is currently a chain of over three dozen separate fragments, named alphabetically, stretching across the sky by several times the angular diameter of the Moon. Hubble caught two of the fragments (B and G) shortly after large outbursts in activity. Hubble shows several dozen "mini-comets" trailing behind each main fragment, probably associated with the ejection of house-sized chunks of surface material. Deep-freeze relics of the early solar system, cometary nuclei are porous and fragile mixes of dust and ices that can break apart due to the thermal, gravitational, and dynamical stresses of approaching the Sun. Whether any of the many fragments survive the trip around the Sun remains to be seen in the weeks ahead. (Courtesy NASA, ESA, JHU/APL, STScI) Comet 73P/Schwassmann-Wachmann 3 - Fragment B: Apr. 18, 2006 Hubble Space Telescope Advanced Camera for Surveys image of Comet 73P/Schwassmann-Wachmann 3 fragment B on April 18, 2006. (Courtesy NASA, ESA, JHU/APL, STScI) Comet 73P/Schwassmann-Wachmann 3 - Fragment B: Apr. 19, 2006 Hubble Space Telescope Advanced Camera for Surveys image of Comet 73P/Schwassmann-Wachmann 3 fragment B on April 19, 2006. (Courtesy NASA, ESA, JHU/APL, STScI) Comet 73P/Schwassmann-Wachmann 3 - Fragment B: Apr. 20, 2006 Hubble Space Telescope Advanced Camera for Surveys image of Comet 73P/Schwassmann-Wachmann 3 fragment B on April 20, 2006. (Courtesy NASA, ESA, JHU/APL, STScI) 1/23/2011 5:41 PM Comet 73P/Schwassmann-Wachmann 3 4 of 4 http://www.solarviews.com/eng/wachmann.htm Comet 73P/Schwassmann-Wachmann 3 - Fragments B, G Ground-based color composite image of Comet 73P/Schwassmann-Wachmann 3 fragments B and G on April 21, 2006 made with a 8" f/1.5 Schmidt Camera. (Courtesy M. J�ger and G. Rhemann) Comet Introduction Views of the Solar System copyright © 1995-2006 by Calvin J. Hamilton. All rights reserved. Privacy Statement. 1/23/2011 5:41 PM Comet Shoemaker-Levy 9 1 of 3 http://www.solarviews.com/eng/levy.htm Custom Search Home | Site Map | What's New | Image Index | Copyright | Puzzles | Posters | ScienceViews | Table of Contents Comet Shoemaker-Levy 9 (This Page) Introduction Views of Shoemaker-Levy 9 Shoemaker-Levy 9 Impact Shoemaker-Levy 9 Image Index Hubble Press Release on the SL-9 Collision Results Comet Tutorial Links to other Comet Shoemaker-Levy Home Pages Comet Shoemaker-Levy 9 Impact from JPL Effelsberg Radio Observations of the Great Comet Crash Comet Shoemake-Levy 9 page from SEDS Introduction Comet Shoemaker-Levy 9 was the ninth short-periodic comet discovered by Eugene and Carolyn Shoemaker and David Levy. It was first detected on a photograph taken on the night of March 24, 1993, with the 0.4-meter Schmidt telescope on Palomar Mountain in California. The magnitude of the comet's brightness was reported as 14, more than a thousand times too faint to be seen with the naked eye. The existence of this object was soon confirmed by James V. Scotti of the Spacewatch program at the University of Arizona. Through the observations and efforts of Brian G. Marsden and other astronomers, the comet's orbit was demonstrated to be around Jupiter and that it had made a very close approach to Jupiter on July 7, 1992. During this close approach, the unequal Jupiter gravitational attractions on the comet's near and far sides broke the fragile object apart. On March 27, an image was taken with the 2.2-m telescope on Mauna Kea in Hawaii that showed as many as 17 separate sub-nuclei strung out like pearls on a string 50 arc seconds long. An early image taken by Scotti on March 30 is shown below. Early Shoemaker/Levy 9 Image On July 1, 1993 an image was taken with the Hubble Space Telescope (HST) that clearly shows at least 15 individual fragments in one image frame of the train. 1/23/2011 5:44 PM Comet Shoemaker-Levy 9 2 of 3 http://www.solarviews.com/eng/levy.htm Early HST Image Since it was not at all obvious where the center of mass of this new comet lay, most observers were using the position of what appeared to be the center of the train. This made an accurate orbit (or orbits) difficult to determine; however, after numerous observations of the comet, astronmers determined that the comet had passed within 96,000 kilometers (60,000 miles) of the center of Jupiter or 25,000 kilometers (16,000 miles) from the cloud tops during the July 8, 1992, approach. They also determined that it would again pass within 25,000 kilometers (16,000 miles) of the center of Jupiter, on July 19, 1994. This distance was less than the radius of Jupiter. In other words, the comet, or at least parts of it, could very well hit Jupiter. Shoemaker-Levy 9 had been in a rapidly changing orbit around Jupiter for some time before this, probably for at least several decades. It did not fragment during earlier approaches to Jupiter because these were made at much greater distances than the 1992 approach. The comet's previous approaches to Jupiter probably came no closer than 9 million kilometers (5.6 million miles). By December 9 1993, the probability of impact for all the large fragments of Shoemaker-Levy 9 was calculated to be greater than 99.99%. The fragments would hit over a period of several days, centered on July 19, on the night side of Jupiter. Unfortunately, this was the back side of Jupiter as viewed from Earth. The impact site would be close to the limb of Jupiter, near 75° from the midnight meridian and only a few degrees beyond the dark limb as seen from Earth. The disruption of a comet into multiple fragments is an unusual event, the capture of a comet into an orbit about Jupiter is even more unusual, and the collision of a large comet with a planet is an extraordinary, millennial event. Views of Shoemaker-Levy 9 HST 1993 Mosaic This high resolution image is a mosaic of images taken by the Hubble Telescope on January 24-27, 1994. Twenty nuclei are visible with one slightly outside of the field-of-view (to the right). Each nucleus has its own coma and tail. The fourth nucleus from the left (the first bright one) is apparently starting to separate into at least two pieces. (Courtesy NASA/JPL) HST Images These images were taken with the Hubble telescope's new camera's on January 24-27, 1994. In the upper image, 20 nuclei are visible with one slightly outside of the field-of-view (to the right). Each nucleus has its own coma and tail. The fourth nucleus from the left (the first bright one) is apparently starting to separate into at least two pieces. The width and height of this image project to distances of 605,000 kilometers (376,000 miles) and 126,500 kilometers (78,600 miles), respectively, at the comet. The lower left and right parts of the screen show the region near the brightest nucleus at higher resolution. To the left is the new image from the corrected camera, while the image to the right shows old data from the aberrated camera. (Courtesy NASA/JPL) Depictions of the Shoemaker-Levy 9 Collision In this series of depictions, comet Shoemaker-Levy 9 impacting Jupiter is shown from three different perspectives: at left, from the viewpoint of Earth; center, from the Voyager 2 spacecraft in the outer reaches of the solar system; and, at right, from Jupiter's south pole. For visual appeal, most of the large cometary fragments are shown close to one another in this image. At the time of Jupiter impact, the fragments will be separated from one another by several times the distances shown. (Courtesy NASA/JPL) Additional Shoemaker-Levy 9 Depictions Viewpoint from the Earth. Viewpoint from Voyager 2. Viewpoint from Juipter's South Pole. Comet Halley's Comet Shoemaker-Levy 9 Impact 1/23/2011 5:44 PM Shoemaker-Levy 9 / Jupiter Impact 1 of 3 http://www.solarviews.com/eng/impact.htm Custom Search Home | Site Map | What's New | Image Index | Copyright | Puzzles | Posters | ScienceViews | Table of Contents Introduction Table of Fragment Impacts and Times Views of Shoemaker-Levy 9 / Jupiter Impact Introduction Fragments of comet P/Shoemaker-Levy 9 collided with Jupiter on July 16-22, 1994. The results were spectacular. At least 20 large fragments impacted the planet at 60 kilometers (37 miles) per second, causing plumes thousands of kilometers high. They left hot bubbles of gas in the atmosphere and great dark scars which lasted for months after the collision. The largest fragments were estimated at 2 kilometers (1.2 miles) in diameter. The fragments impacted Jupiter at approximately 45° south latitude and 6.5° longitude from the limb, and 15° from the dawn terminator just out of view of the Earth. Eleven minutes after impact, the point in the atmosphere where the impact occurred would rotate across the limb and 14 minutes later would cross the dawn terminator. The fragments were moving at an angle of 83° from the Jovian north to south axis and struck the cloud tops at about 45°. The following table lists the impact times as seen from the Earth, calculated by Don Yeomans and Paul Chodes. Fragment A B C D E F G H J K L M N O P1 Q2 Table of Fragment Impacts and Times. Predicted Accepted Date Impact Time Impact Time (July) (HH:MM:SS) & 1-sigma error 16 20:00:40 20:11:00 (3 min) 17 02:54:13 02:50:00 (6 min) 17 17 17 18 18 18 07:02:14 11:47:00 15:05:31 00:29:21 07:28:32 19:25:53 07:12:00 (4 min) 11:54:00 (3 min) 15:11:00 (3 min) 00:33:00 (5 min) 07:32:00 (2 min) 19:31:59 (1 min) 19 19 19 20 20 20 20 02:40 10:18:32 22:08:53 05:45 10:20:02 15:16:20 16:30 Missing since 12/93 10:21:00 (4 min) 22:16:48 (1 min) Missing since 7/93 10:31:00 (4 min) 15:23:00 (7 min) Missing since 3/94 20 19:47:11 19:44:00 (6 min) 1/23/2011 5:44 PM Shoemaker-Levy 9 / Jupiter Impact 2 of 3 http://www.solarviews.com/eng/impact.htm Q1 R S T U V W 20 21 20:04:09 05:28:50 20:12:00 (4 min) 05:33:00 (3 min) 21 21 21 15:12:49 18:03:45 21:48:30 15:15:00 (5 min) 18:10:00 (7 min) 21:55:00 (7 min) 22 22 04:16:53 07:59:45 04:22:00 (5 min) 08:05:30 (3 min) Views of Shoemaker-Levy 9 / Jupiter Impact Galileo Image of Impact W These four images of Jupiter and the luminous night-side impact of fragment W of Comet Shoemaker-Levy 9 were taken by the Galileo spacecraft on July 22, 1994. The spacecraft was 238 million kilometers (148 million miles) from Jupiter at the time, and 621 million kilometers (386 million miles) from Earth. The spacecraft was about 40 degrees from Earth's line of sight to Jupiter, permitting this direct view. The first image, taken at an equivalent time to 8:06:10 Greenwich Mean Time (1:06 a.m. Pacific Daylight Time), shows no impact. In the next three images, a point of light appears, brightens so much as to saturate its picture element, and then fades again, seven seconds after the first picture. The location is approximately 44 degrees south as predicted; dark spots to the right are from previous impacts. Jupiter is approximately 60 picture elements in diameter. (Courtesy NASA) Impact of H-fragment observed at La Silla This image was obtained with the TIMMI instrument at the European Southern Observatory's 3.6-meter telescope on July 18, 1994, 20:11 UT. It shows the rising plume above the impact site of fragment H of comet Shoemaker-Levy 9. The image was made in the 9.1 - 10.4 micron band in the far-infrared region. The surface brightness of this plume was about 50 times that of the Jupiter disk. The temperature was measured as more than 300 K. (Courtesy European Southern Observatory) HST UV Image of Impacts H, Q1, R, D, G, L, B, N & Q2 This ultraviolet image shows Jupiter's atmosphere at a wavelength of 2550 Angstroms after many impacts by fragments of comet Shoemaker-Levy 9. The most recent impactor is fragment R which is below the center of Jupiter (third dark spot from the right). This photo was taken by the Hubble Space Telescope at 3:55 EDT on July 21, about 2.5 hours after R's impact. A large dark patch from the impact of fragment H is visible rising on the morning (left) side. Proceeding to the right, other dark spots were caused by impacts of fragments Q1, R, D and G (now one large spot), and L, with L covering the largest area of any seen thus far. Small dark spots from B, N, and Q2 are visible with careful inspection of the image. The spots are very dark in the ultraviolet because a large quantity of dust is being deposited high in Jupiter's stratosphere, and the dust absorbs sunlight. (Courtesy Hubble Space Telescope Comet Team) HST Image of Impacts E/F, H, N, Q1, Q2, R and D/G Image of Jupiter with the Hubble Space Telescope Planetary Camera. Eight impact sites are visible. From left to right are the E/F complex (barely visible on the edge of the planet), the star-shaped H site, the impact sites for tiny N, Q1, small Q2, and R, and on the far right limb the D/G complex. The D/G complex also shows extended haze at the edge of the planet. The features are rapidly evolving on time scales of days. The smallest features in this image are less than 200 kilometers (124 miles) across. (Courtesy Hubble Space Telescope Comet Team) HST Image of Impacts D and G This image of Jupiter shows the impact sites of fragments "D" and "G" from Comet Shoemaker-Levy 9. The large feature was created by the impact of fragment "G" on July 18, 1994 at 3:28 a.m. EDT. It entered Jupiter's atmosphere from the south at a 45-degree angle, and the resulting ejecta appears to have been thrown back along that direction. The smaller feature to the left of the fragment "G" impact site was created on July 17, 1994, at 7:45 a.m. EDT by the impact of fragment "D". The "G" impact has concentric rings around it, with a central dark spot 2,500 kilometers (1,550 miles) in diameter. This dark spot is surrounded by a thin dark ring 7,500 kilometers (4,661 miles) in diameter. The dark thick outermost ring's inner edge has a diameter of 12,000 kilometers (7,460 miles) - about the size of the Earth. (Courtesy Hubble Space Telescope Comet Team) HST Views of Comet Fragment G Impact Zone This image shows two views of the impact zone on Jupiter of fragment G of Comet Shoemaker-Levy 9. The image on the left was made in green light. The image on the right is the same field taken through a methane filter. These images were obtained by the Hubble Space Telescope in the early morning of July 18, 1994. The impact site is visible as a complex pattern of circles seen in the lower left of the partial planet image. The small dark feature to the left of the pattern of circles is the impact site of fragment D. The dark, sharp ring at the site of the fragment G impact is 80% of the size of the Earth. (Courtesy Dr. Heidi Hammel, Massachusetts Institute of Technology/NASA HST) 1/23/2011 5:44 PM Shoemaker-Levy 9 / Jupiter Impact 3 of 3 http://www.solarviews.com/eng/impact.htm HST G Plume Image These images taken by the Hubble Telescope show the G impact site through methane, red, green, blue and violet filters. (Courtesy Hubble Space Telescope Comet Team) HST A, C and E Impact Sites This Hubble image of Jupiter was obtained with a filter at 336 nm (near-ultraviolet light) at 18:42 UT on 17 July 1994. Three impact sites (from left to right: C, A, and E) are visible as dark spots across the lower portion of the image. All other features in this picture are characteristic of Jupiter's normal state. The feature created by the impact of A is 23 hours old in this image. The C and E features are 12 and 5 hours old, respectively. Io is seen on the left as a dark spot in the northern hemisphere, and the Great Red Spot is visible on the right limb. (Courtesy Hubble Space Telescope Jupiter Imaging Team) Evolution of the G Impact Site This mosaic of Hubble images shows the evolution of the G impact site on Jupiter. The images from lower right to upper left show: the impact plume at 07/18/94 07:38 UT (about 5 minutes after the impact); the fresh impact site at 07/18/94 at 09:19 UT (1.5 hours after impact); the impact site after evolution by the winds of Jupiter (left), along with the L impact (right), taken on 07/21/94 at 06:22 UT (3 days after the G impact and 1.3 days after the L impact); and further evolution of the G and L sites due to winds and an additional impact (S) in the G vicinity, taken on 07/23/94 at 08:08 UT (5 days after the G impact). (Credit: R. Evans, J. Trauger, H. Hammel and the HST Comet Science Team and NASA) IRTF Infrared Image of Q & R Impacts This is a 2.07 micron image of Jupiter taken on the NASA Infrared Telescope Facility, Mauna Kea, Hawaii, at 08:54 on July 21, 1994. Io, the closest of the jovian moons, can be seen crossing the planet in the northwest of the image (top right). The Great Red Spot is visible in the south east of the planet. At the collision latitudes, the impact due to Fragment Q is just setting on the west. Just to the east of it, the R Fragment impact site shows up very brightly. Another four impact sites form a chain of spots behind R. (Courtesy NASA IRTF Comet Science Team) Comet SL9 Background Kuiper Belt Objects Views of the Solar System Copyright © 1997-2009 by Calvin J. Hamilton. All rights reserved. Privacy Statement. 1/23/2011 5:44 PM Hubble Observations Shed New Light on Jupiter Collision 1 of 2 http://www.solarviews.com/eng/levyhst.htm Custom Search Home | Site Map | What's New | Image Index | Copyright | Puzzles | Posters | ScienceViews | Was it a comet or an asteroid? Scientists are debating that question as they continue to pore over Hubble Space Telescope imaging and spectroscopic data gleaned in the wake of the spectacular July 1994 bombardment of Jupiter by comet P/Shoemaker-Levy 9. Their initial findings, combined with results from other space-borne and ground-based telescopes, shed new light on Jupiter's atmospheric winds, its immense magnetic field, the mysterious dark debris from the impacts, and the composition of the doomed comet itself. The Last Days Of The Comet Before the comet impact, there was a great deal of speculation and prediction about whether the 21 nuclei would survive before reaching Jupiter, or were so fragile that gravitational forces would pull them apart into thousands of smaller fragments. Hubble helped answer this question by watching the nuclei until about 10 hours before impact. HST's high resolution images show that the nuclei, the largest of which were probably a few kilometers across, did not break up catastrophically before plunging into Jupiter's atmosphere. This reinforces the notion that the atmospheric explosions were produced by solid, massive impacting bodies. HST's resolution also showed that the nuclei were releasing dust all along the path toward Jupiter, as would be expected from a comet. This was evident in the persistence of spherical clouds of dust surrounding each nucleus throughout most of the comet's journey. About a week before impact, these dust clouds were stretched out along the path of the comet's motion by Jupiter's increasingly strong gravity. Was P/Shoemaker-Levy 9 A Comet Or An Asteroid? At present, observations seem to slightly favor a cometary origin, though an asteroidal origin cannot yet be ruled out. The answer isn't easy because comets and asteroids have so much in common: they are small bodies; they are primordial, having formed 4.6 billion years ago along with the planets and their satellites; either type of object can be expected to be found in Jupiter's vicinity. The key difference is that comets are largely icy while the asteroids are virtually devoid of ice because they formed too close to the Sun. What Is That Dark Stuff Made Of? The HST Faint Object Spectrograph (FOS) detected many gaseous absorptions associated with the impact sites and followed their evolution over the next month. Most surprising were the strong signatures from sulfur-bearing compounds like diatomic sulfur (S2), carbon disulfide (CS2), and hydrogen sulfide (H2S). Ammonia (NH3) absorption also was detected. The S2 absorptions seemed to fade on timescales of a few days, while the NH3 absorptions at first got stronger with time, and finally started fading after about one month. During observations near the limb of Jupiter, the FOS detected emissions from silicon, magnesium and iron that could only have originated from the impacting bodies, since Jupiter itself normally does not have detectable amounts of these elements. Swept Across Jupiter Observations made with HST's Wide Field Planetary Camera-2, a week and a month after impact, have been used to make global maps of Jupiter for tracking changes in the dark debris caught up in the high-speed winds at Jupiter's cloudtops. This debris is a 1/23/2011 5:45 PM Hubble Observations Shed New Light on Jupiter Collision 2 of 2 http://www.solarviews.com/eng/levyhst.htm natural tracer of wind patterns and allows astronomers a better understanding of the physics of the Jovian atmosphere. The high speed easterly and westerly jets have turned the dark "blobs" originally at the impact sites into striking "curly-cue" features. Although individual impact sites were still visible a month later despite the shearing, the fading of Jupiter's scars has been substantial and it now appears that Jupiter will not suffer any permanent changes from the explosions. Hubble's ultraviolet observations show the motion of very fine impact debris particles now suspended high in Jupiter's atmosphere. The debris eventually will diffuse down to lower altitudes. This provides the first information ever obtained about Jupiter's high altitude wind patterns. Hubble gives astronomers a "three dimensional" perspective showing the wind patterns at high altitudes and how they differ from those at the visible cloudtop level. At lower altitudes, the impact debris follows east-west winds driven by sunlight and Jupiter's own internal heat. By contrast, winds in the high Jovian stratosphere move primarily from the poles toward the equator because they are driven mainly by auroral heating from high energy particles. Piercing Jupiter's Magnetic Field About four days before impact, at a distance of 2.3 million miles from Jupiter, nucleus "G" of comet P/Shoemaker-Levy 9 apparently penetrated Jupiter's powerful magnetic field, the magnetosphere. (Jupiter's magnetosphere is so vast, if visible from Earth, it would be about the size of the full Moon.) Hubble's Faint Object Spectrograph (FOS) recorded dramatic changes at the magnetosphere crossing that provided a rare opportunity to gather more clues on the comet's true composition. During a two-minute period on July 14, HST detected strong emissions from ionized magnesium (Mg II), an important component of both comet dust and asteroids. However, if the nuclei were ice-laden - as expected of a comet nucleus - astronomers expected to detect the hydroxyl radical (OH). Hubble did not see OH, casting some doubt on the cometary nature of comet P/Shoemaker-Levy 9. Eighteen minutes after comet P/Shoemaker- Levy 9 displayed the flare-up in Mg II emissions, there was also a dramatic change in the light reflected from the dust particles in the comet. New Auroral Activity HST detected unusual auroral activity in Jupiter's northern hemisphere just after the impact of the comet's "K" fragment. This impact completely disrupted the radiation belts which have been stable over the last 20 years of radio observations. Aurorae, glowing gases that create the northern and southern lights, are common on Jupiter because energetic charged particles needed to excite the gases are always trapped in Jupiter's magnetosphere. However, this new feature seen by Hubble was unusual because it was temporarily as bright or brighter than the normal aurora, short-lived, and outside the area where Jovian aurorae are normally found. Astronomers believe the K impact created an electromagnetic disturbance that traveled along magnetic field lines into the radiation belts. This scattered charged particles, which normally exist in the radiation belts, into Jupiter's upper atmosphere. X-ray images taken with the ROSAT satellite further bolster the link to the K impact. They reveal unexpectedly bright X-ray emissions that were brightest near the time of the K impact, and then faded. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA). Donald Savage Headquarters, Washington, D.C. September 29, 1994 (Phone: 202/358-1547) Jim Elliott Goddard Space Flight Center, Greenbelt, Md. (Phone: 301/286-6256) Ray Villard Space Telescope Science Institute, Baltimore, Md. (Phone: 410/338-4514) RELEASE: 94-161 Comet Shoemaker-Levy 9 Views of the Solar System Copyright © 1997-2009 by Calvin J. Hamilton. All rights reserved. Privacy Statement. 1/23/2011 5:45 PM 109P/Swift-Tuttle - Wikipedia, the free encyclopedia 1 of 2 http://en.wikipedia.org/wiki/109P/Swift-Tuttle From Wikipedia, the free encyclopedia Comet Swift-Tuttle (formally designated as 109P/Swift-Tuttle) is a comet that was independently discovered by Lewis Swift on July 16, 1862 and by Horace Parnell Tuttle on July 19, 1862. The comet made a return appearance in 1992, when it was rediscovered by Japanese astronomer Tsuruhiko Kiuchi and became visible with binoculars.[1] Its solid nucleus is about 27 kilometers (16.8 miles) across, considerably larger than the 10 km object hypothesized to have wiped out the dinosaurs in the Cretaceous–Paleogene extinction event.[2] It is the parent body of the Perseid meteor shower, perhaps the best known shower and among the most reliable in performance. [3] An unusual aspect of its orbit is that it is presently captured into a 1:11 orbital resonance with Jupiter; it completes one orbit for every 11 of Jupiter.[4] 109P/Swift-Tuttle Discovery Discovered by: Lewis Swift Horace Parnell Tuttle Discovery date: July 16, 1862 Alternate 1737 N1; 1737 II; 1862 designations: O1; 1862 III; 1992 S2; 1992 XXVIII Orbital characteristics A (http://www.minorplanetcenter.org/iau/Ephemerides /Comets/) October 10, 1995 (JD 2450000.5) Aphelion distance: 51.225 AU Perihelion distance: 0.9595 AU Semi-major axis: 26.092 AU Eccentricity: 0.9632 Orbital period: 133.28 a Inclination: 113.45° Last perihelion: December 11, 1992 Next perihelion: July 12, 2126 Epoch: The comet is on an orbit which puts it close to the Earth and the Moon.[5] Upon its 1992 rediscovery, the comet's date of perihelion passage was off from the then-current prediction by 17 days. It was then noticed that, if its next perihelion passage (August 14, 2126) was also off by another 15 days, the comet would very likely strike the Earth or Moon. Given the size of the nucleus of Swift-Tuttle, this was of some concern. This prompted amateur astronomer and writer Gary W. Kronk to search for previous apparitions of this comet. He found the comet was most likely observed by the Chinese in 69 BC and AD 188, which was quickly confirmed by Brian G. Marsden.[6] This information and subsequent observations have led to recalculation of its orbit, which indicates the comet's orbit is very stable, and that there is absolutely no threat over the next two thousand years.[7] Astronomers believe that in the 2126 pass it will likely be a great naked-eye comet like Hale-Bopp.[1] A close encounter with Earth is predicted for the comet's return to the inner solar system in the year 4479, around Sept. 15; the closest approach is estimated to be 0.03-0.05 AU, with a probability of impact of 1 × 10−6.[4] Subsequent to 4479, the orbital evolution of the comet is more difficult to predict; the probability of Earth impact per orbit is estimated as 2 × 10−8.[4] As the largest Solar System object that makes repeated close passes of Earth, and which does so at a relative velocity of 60 km/s,[2][8] leading to an estimated impact energy of ~27 times that of the K-T impactor,[9] Comet Swift-Tuttle has been described as "the single most dangerous object known to humanity".[8] 1. ^ a b Britt, Robert (2005-08-11). "Top 10 Perseid Meteor Shower Facts" (http://www.space.com/spacewatch /050811_perseid_facts.html) . Space.com. http://www.space.com/spacewatch/050811_perseid_facts.html. Retrieved 1/23/2011 5:50 PM C&MS: 109P/Swift-Tuttle 1 of 3 http://cometography.com/pcomets/109p.html G A R Y W. K R O N K ' S C O M E T O G R A P H Y Past, Present, and Future Orbits by Kazuo Kinoshita Copyright © 1992 by Herman Mikuz (Crni Vrh Observatory, Slovenia) This image was obtained on 1992 December 15, with 3.5/250mm lens, CCD, and narrow-band H2O+ filter, centered at 620nm (FWHM=10nm). The field of view is 2.9x1.9 degrees. (The webmaster has inverted the image to better represent the appearance of the comet.) Lewis Swift (Marathon, New York, USA) discovered this comet in Camelopardalis on 1862 July 16, while examining the northern sky with his 11.4-cm Fitz refractor. He described the comet as a somewhat bright telescopic object, but did not report it since he thought he was observing the comet Schmidt had found on July 2. Without knowledge of Swift's observation, Horace Parnell Tuttle (Harvard College Observatory, Cambridge, Massachusetts, USA) independently discovered this comet on July 19.19 and noted it was heading northward. He then made an official announcement. When Swift heard of Tuttle's find, he immediately realized the comet seen on July 16 was not Schmidt's and made his announcement to get credit for his first comet discovery. There were several independent discoveries. Thomas Simons (Dudley Observatory, Albany, New York, USA) independently discovered the comet on July 19.30. He remarked, "When first seen it appeared as a nebula considerably condensed at the centre, the light being intense enough to be easily observed when the wires of the micrometer were illuminated." Antonio Pacinotti and Carlo Toussaint (Florence, Italy) found the comet on July 22. Schjellerup (Copenhagen) found this comet in Camelopardalis on the night of July 26/27. He described it as a bright nebulosity with a very slow movement. On July 27.98, Schjellerup and d'Arrest confirmed the discovery with a large refractor. Schjellerup remarked, "The comet is rather bright, the nucleus equalled a star of 7th magnitude." He added that at a magnification of 226x they saw a distinct extension in the direction of the sun, while the surrounding nebulosity was 3 arc minutes across. On 1/23/2011 5:51 PM C&MS: 109P/Swift-Tuttle 2 of 3 http://cometography.com/pcomets/109p.html September 1, John Tebbutt (Windsor, New South Wales) independently discovered this comet, not yet having received a notification of its prior discovery. With a 3.25-inch telescope, he noted the comet's nucleus was badly defined and did not admit accurate determinations of position. J. F. Julius Schmidt (Athens, Greece) made numerous observations of the comet from 1862 August to September. He examined his magnitude estimates of the comet's nucleus and determined that, on the average, maximum light occurred every 2.691±0.269 days, while minimum light occurred every 2.711±0.284 days. The earliest orbits were computed at the end of July and in early August. These were parabolic orbits indicating a perihelion date of 1862 August 22 to 24. During the next few years several astronomers computed elliptical orbits indicating an orbital period between 120 and 125 years, with the first attempt at a definitive orbit coming in 1889 when F. Hayn determined the orbital period as 119.64 years. During 1971, B. G. Marsden and Zdenek Sekanina took 212 positions obtained during the period of 1862 July 22 to October 22, applied perturbations by all nine planets, and determined the orbital period as 119.98 years. A couple of years later, Marsden looked at the possibility of trying to link Swift-Tuttle to an earlier comet. He found two in the 18th century that looked promising--1737 (Kegler) and 1750 (Wargentin). The 1750 comet appeared at just about the right time expected for Swift-Tuttle if that comet's motion was integrated back from 1862. The problem, however, was that it was moving too fast. The 1737 comet actually exhibited a motion consistent for what would have been expected for Swift-Tuttle if the perihelion date had fallen on June 15 of that year; however, as Marsden pointed out, the main point this identity "is that the comet's osculating period would have to have been some 10 yr longer than is indicated by the observations in 1862." Marsden made two predictions for a forthcoming return. First, using the definitive orbit of Sekanina and himself, he suggested a perihelion date of 1981 September 16.93. Second, he suggested that if the link to the comet of 1737 was valid, the comet would likely return to perihelion on 1992 November 25.85. Minor searches for the comet began in 1980, which was within the error range given by calculations, and more rigorous searches were conducted in 1981 and 1982, but nothing was found. Tsuruhiko Kiuchi (Japan) discovered a comet on 1992 September 26.76 and reported it to the National Astronomical Observatory (Tokyo). He said it was magnitude 11.5. H. Kosai of that observatory subsequently reported it to the (Central Bureau for Astronomical Telegrams) and suggested it might be comet Swift-Tuttle. Several observers were able to confirm the comet within the next 24 hours and the indicated direction and rate of motion was consistent with what would be expected for Swift-Tuttle. Brian G. Marsden (Central Bureau) was not able to do a precise linkage between the 1862 and 1992 positions, but he did provide an orbit that adequately represented all available positions. It indicated a perihelion date of 1992 December 12.29, a perihelion distance of 0.959 AU, and an orbital period of 135.29 years. Observations made within the first days following the recovery revealed the comet's actual magnitude was near 9 and that the coma diameter was about 4 arc minutes.The comet steadily brightened during the following weeks. It surpassed magnitude 8.5 shortly after October began and had climbed to 6.0 by the beginning of November. A faint tail over a degree long was already visible on photographs after mid-October and this continued to brighten during the following weeks. By mid-November it was possible to see over 2 degrees of tail with binoculars. Along other lines of observation, astronomers reported that observations during the first half of November were revealing the production rates of various gases, of which OH, Methanol, CS, and water were among the first identified. The comet surpassed magnitude 5.0 right at mid-November and continued brightening. The ion tail was 6.7 degrees long on November 23 when Herman Mikuz (Slovenia) imaged it with 10-minute exposure CCD frames. Most interesting was a report by L. Jorda and J. Lecacheux (Paris-Meudon) and F. Colas (Observatoire de Paris) that observations of a nuclear jet with the 1.05-m telescope and CCD camera at Pic du Midi over the period of November 20-26 indicated a probable nuclear rotation period of 2.9 days. Compare this to the periodicity earlier noted by Schmidt in the brightness of the nucleus back in 1862. As November came to a close brightness estimates were still at 5.0 and the comet showed no sign of fading until just before mid-December. 1/23/2011 5:51 PM C&MS: 109P/Swift-Tuttle 3 of 3 http://cometography.com/pcomets/109p.html Copyright © 1992 by Gerald Rhemann This image was obtained on 1992 November 24.74 UT with the 171/200/257mm Schmidt camera. Exposure time was 10 minutes and the photographic emulsion was Kodak Ektachrome 100. The comet's total magnitude was then about 5.0. (The image has been cropped by the webmaster to save space.) By early December of 1992 it was becoming obvious that independent orbital calculations by Marsden and Donald K. Yeomans which attempted to fit the 1862 and 1992 observations were becoming increasing further off the mark in predicting the motion of this comet. Marsden attempted a nongravitational solution and managed the best fit of the available positions, but noted large discrepancies in the positions of 1862 October. Interestingly, this new orbit allowed two prediscovery images to be located. The first was found by R. Haver (Cima Ekar) on a plate exposed with a 0.4-m f/2.5 Schmidt on 1992 January 3.08. The comet was described as stellar with a magnitude of 17.5. The second was found by L. Kohoutek (Calar Alto) on a plate exposed on January 7.09 with a 0.8-m Schmidt. He estimated the magnitude as 18. Around this time, Gary Kronk (Troy, Illinois, USA) announced the liklihood that comets reported by the Chinese in -68 and +188 were good candidates for Swift-Tuttle. Independent computations by Marsden and G. Waddington (Oxford University) confirmed the links and noted a purely gravitational solution worked better to fit the apparitions. In addition, it was realized that no favorable apparitions would have occurred following 188 until 1737. The comet was last seen on 1995 March 29.48, by observers at Siding Spring Observatory (Australia). cometography.com Current Comets | Periodic | Sungrazers | Links | Comet Information Meteor Showers Online Media Inquiries 1/23/2011 5:51 PM