* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download No. 53 - Institute for Astronomy
Perseus (constellation) wikipedia , lookup
James Webb Space Telescope wikipedia , lookup
Planets beyond Neptune wikipedia , lookup
Geocentric model wikipedia , lookup
History of Mars observation wikipedia , lookup
Formation and evolution of the Solar System wikipedia , lookup
Circumstellar habitable zone wikipedia , lookup
Kepler (spacecraft) wikipedia , lookup
Space Interferometry Mission wikipedia , lookup
Cygnus (constellation) wikipedia , lookup
Astrophotography wikipedia , lookup
History of Solar System formation and evolution hypotheses wikipedia , lookup
IAU definition of planet wikipedia , lookup
Aquarius (constellation) wikipedia , lookup
Late Heavy Bombardment wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Star formation wikipedia , lookup
Theoretical astronomy wikipedia , lookup
Exoplanetology wikipedia , lookup
Definition of planet wikipedia , lookup
Corvus (constellation) wikipedia , lookup
Dialogue Concerning the Two Chief World Systems wikipedia , lookup
International Ultraviolet Explorer wikipedia , lookup
Rare Earth hypothesis wikipedia , lookup
Astronomical naming conventions wikipedia , lookup
History of astronomy wikipedia , lookup
Planetary system wikipedia , lookup
Spitzer Space Telescope wikipedia , lookup
Planetary habitability wikipedia , lookup
Ancient Greek astronomy wikipedia , lookup
Astrobiology wikipedia , lookup
Observational astronomy wikipedia , lookup
FOR AS T RO NOMY INSTITU TE i ‘i U ni ve wa rsit y of Ha Nā Kilo Hōkū The Ones Who Look to the Stars No. 53 • 2015 A Newsletter from the Institute for Astronomy University of Hawai‘i www2.ifa.hawaii.edu/newsletters Artist’s conception of the 30 Ari star system. The system is composed of four stars. The distant companion 30 Ari A is actually a pair of stars in a close orbit. The research team discovered the fourth star in the system (the left-most star in the image). That star is a small red dwarf. A massive planet orbits the star named 30 Ari B in a nearly year-long orbit. Art by Karen Teramura, UH IfA One Planet, Four Stars Contents 3. Mānoa Open House 4. Clues to atmospheres on Earth-size exoplanets in the habitable zone 5. Fastest known star in our galaxy 6. UHNAI researcher finds new microbes 7. HI STAR students at science fairs 8. From the Director Free Public Events www.ifa.hawaii.edu/specialevents/ April 12, 11:00 a.m.–4:00 p.m. UH IfA Mānoa Open House Free admission and parking May 2, 11:00 a.m. – 4:00 p.m. Maunakea Outreach ‘Ohana presents AstroDay at Hilo’s Prince Kūhiō Plaza Researchers, including IfA’s Christoph Baranec, who want to know more about the influences of multiple stars on exoplanets have found only the second known case of a planet in a four-star system. Although the star system, 30 Ari, was previously known to scientists, the new study increases the number of stars in it from three to four. The system is located 136 light-years away in the constellation Aries. Its gaseous planet is enormous, with 10 times the mass of Jupiter, and orbits its primary star every 335 days. The newly discovered fourth star, whose distance from the planet is 23 times the Sun-Earth distance, does not appear to have impacted the orbit of the planet. The exact reason for this is uncertain, so the team is planning further observations to better understand the orbit of the newly discovered star and its complicated family dynamics. Were it possible to see the skies from this world, the four stars would look like one small sun and two very bright stars that would be visible in daylight. If viewed with a large enough telescope, one would see that one of those bright stars is actually a binary system—two stars orbiting each other. Please see 30 Ari, pg 2 Mars Once Had an Ocean and Perhaps Life A primitive ocean on Mars held more water than Earth’s Arctic Ocean, according to a NASA-sponsored study that IfA astronomer Alan Tokunaga and graduate student Alain Khayat participated in. About 4.3 billion years ago, Mars would have had enough water to cover its entire surface in a liquid layer about 450 feet (137 m) deep. More likely, the water would have formed an ocean occupying almost half of Mars’ northern hemisphere, in some regions reaching depths greater than a mile (1.6 km). The wetter conditions mean that life was more likely to have existed on Mars than previously thought. This new estimate is based on detailed observations made at the European Southern Observatory’s Very Large Telescope in Chile, and the W.M. Keck Observatory and NASA Infrared Telescope Facility in Hawai‘i. Tokunaga and Khayat gathered data with the two Hawai‘i telescopes. The scientists used the ground-based observatories to measure water signatures in the Red Planet’s atmosphere. They distinguished the chemical signatures of two slightly different forms of water in Mars’ atmosphere. One is the familiar H2O. The other is HDO, a naturally occurring variation in which one hydrogen atom is replaced by a heavier atom called deuterium. By comparing the ratio of HDO to H2O in water on Mars today with the ratio in water trapped in a Mars meteorite dating from about 4.5 billion years ago, scientists measured the subsequent atmospheric changes and determined how much water has escaped into space. The team mapped H2O and HDO levels several times over nearly six years, which is equal to approximately three Martian years. The resulting data produced global snapshots of each compound, as well as their ratio. These first-of-their-kind maps reveal regional variations called microclimates and seasonal changes, even though modern Mars is essentially a desert. Please see Mars’ Ocean, pg 2 30 Ari Continued from pg 1 In recent years, dozens of planetary systems with two or three host stars have been found, which isn’t too much of a surprise, considering that binary stars are more common in our galaxy than single stars such as our Sun. “About four percent of solar-type stars are in quadruple systems, which is up from previous estimates because observational techniques are steadily improving,” said Andrei Tokovinin (Cerro Tololo Inter-American Observatory, Chile), a co-author of the study. Lead author Lewis Roberts (Jet Propulsion Laboratory) and his colleagues want to understand the effects that multiple stars can have on their developing youthful planets. Evidence suggests that stellar companions can influence the fate of planets by changing the planets’ orbits and even triggering some to grow more massive. The “hot Jupiter” planets that whip around their stars in just days, for example, might be gently nudged closer to their primary star by the gravitational hand of a stellar companion. “This result strengthens the connection between multiple star systems and massive planets,” said Roberts. The discovery was made at Palomar Observatory using two new adaptive optics technologies that compensate for the blurring effects of Earth’s atmosphere: the robotic Robo-AO adaptive optics system, developed under the leadership of Baranec, and the PALM-3000 extreme adaptive optics system, developed by a team at Caltech and NASA’s Jet Propulsion Laboratory (JPL) that also included Baranec. targets,” said Baranec. “At the moment, Robo-AO is the only instrument that can give us the necessary combination of resolution and efficiency. Once we discover something interesting with Robo-AO, we can follow up with the ‘Formula 1’ systems, like PALM-3000 or the SCExAO system at the Subaru Telescope in Hawai‘i, to obtain the absolute sharpest images possible. Additionally, we’re planning to bring a new, more powerful Robo-AO system to the University of Hawai‘i 2.2-m telescope to leverage the pristine skies of Maunakea. We’ll use it for even larger surveys and follow-up observations of asteroids and supernovae discovered by ATLAS on Mauna Loa and Haleakalā.” “The discovery of this exciting system is only possible when we quickly scan through large numbers of potential For information about Robo-AO, www.ifa.hawaii.edu/Robo-AO/ For information about ATLAS, fallingstar.com Mar’s Ocean Continued from pg 1 From the measurements of atmospheric water in the near-polar region, the researchers determined the enrichment, or relative amounts of the two types of water, in the planet’s permanent ice caps. The enrichment of the ice caps told them how much water Mars must have lost—a volume 6.5 times larger than the volume in the polar caps now. That means the volume of Mars’ early ocean must have been at least 5 million cubic miles (20 million cubic kilometers). Based on the surface of Mars today, a likely location for this water would have been the Northern Plains, considered a good candidate because of the low-lying ground. An ancient ocean there would have covered 19 percent of the planet’s surface. By comparison, the Atlantic Ocean occupies 17 percent of Earth’s surface. A primitive ocean on Mars held more water than Earth’s Arctic Ocean, but the Red Planet has lost 87 percent of that water to space. Image Credit: NASA’s Goddard Space Flight Center A primitive ocean on Mars held more water than Earth’s Arctic Ocean, but the Red Planet has lost 87 percent of that water to space. Image by NASA’s Goddard Space Flight Center. 2 Open House 2015 Join us for our annual Open House on Sunday, April 12, from 11 a.m. to 4 p.m. at our Mānoa headquarters located at 2680 Woodlawn Drive. The theme for this year is the International Year of Light proclaimed by the United Nations General Assembly to raise awareness of the importance of light and light-based technologies for sustainable development. Light-related activities will include observing the Sun through telescopes, astrophotography, an infrared camera that will allow you to see what you look like at infrared wavelengths, a talk about the invisible (to our eyes) Universe, and a spectroscopy school where you will learn about the different kinds of light, such as infrared or ultraviolet, and what they can tell us about distant bodies. You will be able to experience air-powered rockets brought by UH Mānoa SUPER-M (as in mathematics), hands-on physics toys brought by the staff of the Windward Community College Imaginarium, a 3-D printer demonstration, and a wind tunnel courtesy of the Pacific Aviation Museum. The Bishop Museum is bringing its brand new Digitalis portable planetarium so you can explore the night sky, and the Polynesian Voyaging Society will be there, too. The CAVE, a 3-D virtual environment, will again be available for tours, and as usual you will be able to Ask an Astronomer, who will be wearing a funny hat. For the keiki, there will be face painting, sundial making, and bottle-rocket launching. There will be talks and videos on a variety of astronomy-related topics. Of special note is the talk by Brent Tully, who will explain the Laniakea Supercluster, a vast collection of over 100,000 galaxies whose Hawaiian name honors the Polynesian navigators who used their knowledge of the heavens to cross the immense Pacific Ocean. Admission and parking will be free. For the latest information, see www.ifa.hawaii.edu/open-house/. 3 Three-Planet System Holds Clues to Atmospheres of Earth-size Worlds This whimsical cartoon shows the three newly discovered Extrasolar planets are being discovered by the hundreds, but are any of these newfound worlds really like Earth? A planetary system recently discovered by the Kepler spacecraft will help resolve this question. The system of three planets, each just larger than Earth, orbits a nearby star called EPIC 201367065. The three planets are 1.5–2 times the size of Earth, and the outermost planet orbits on the edge of the so-called “habitable zone,” where the temperature may be just right for liquid water, believed necessary to support life, on the planet’s surface. “We’ve learned in the past year that planets the size and temperature of Earth are common in our Milky Way galaxy,” explains IfA astronomer Andrew Howard. “We also discovered some Earth-size planets that appear to be made of the same materials as our Earth, mostly rock and iron.” The compositions of these newfound planets are unknown. “There is a very real possibility that the outer planet is rocky like Earth,” noted Erik Petigura, a University of California, Berkeley graduate student who spent a year visiting the IfA. “If so, this planet could have the right temperature to support liquid water oceans.” In addition to Howard and Petigura, IfA graduate students Benjamin Fulton and Kimberly Aller, and IfA as- tronomer Michael Liu are among the two dozen scientists who contributed to the study. The planets were confirmed by the NASA Infrared Telescope Facility (IRTF) and the W.M. Keck Observatory in Hawai‘i, as well as telescopes in California and Chile. The new discovery paves the way for studies of the atmosphere of a warm planet nearly the size of Earth. The three new planets are particularly favorable for atmospheric studies because they orbit a nearby, bright star. Next, the team of astronomers that made the discovery hopes to observe the planets with the Hubble Space Telescope and other observatories to determine what elements are in the planets’ atmospheres. If Hubble finds that these warm, nearly Earth-size planets have thick, hydrogen-rich atmospheres, they will learn that there is not much chance for life. “A thin atmosphere made of nitrogen and oxygen has allowed life to thrive on Earth. But nature is full of surprises. Many extrasolar planets discovered by the Kepler Mission are enveloped by thick, hydrogen-rich atmospheres that are probably incompatible with life as we know it,” says Ian Crossfield, the University of Arizona astronomer who led this study. The discovery is all the more remarkable because Kepler is now hobbled by the loss of two reaction wheels that kept it pointing at a fixed spot in space. Kepler, extrasolar planets (right) casting shadows on their host star that can been seen as eclipses, or transits, at Earth (left). Earth can be detected by the same effect, but only in the plane of Earth’s orbit (the ecliptic). During the K2 mission, many of the extrasolar planets discovered by the Kepler telescope will have this lucky double cosmic alignment that would allow for mutual discovery—if there is anyone on those planets to discover Earth. The three new planets orbiting EPIC 201367065 are just out of alignment; while they are visible from Earth, our solar system is tilted just out of their view. Art by K. Teramura, UH IfA. launched in 2009, was reborn in 2014 as “K2” with a clever strategy of pointing the telescope in the plane of the Earth’s orbit to stabilize the spacecraft. Kepler is back to mining the cosmos for planets by searching for eclipses, or transits, as planets orbit in front of their host stars and periodically block some of the starlight. Kepler sees only a small fraction of the planetary systems in its gaze, those with orbital planes aligned edge-on to our view from Earth. Planets with large orbital tilts are simply missed by Kepler. The planets orbiting EPIC 201367065 were not the first discovered by the K2 mission. That distinction belongs to HIP 116454b, which is two and a half times the size of Earth. IfA astronomer Christoph Baranec supplied confirming data for this discovery with his Robo-AO instrument mounted on the Palomar 1.5-meter telescope. 4 Fastest Star in Our Galaxy Propelled by a Thermonuclear Supernova A team of astronomers, including IfA astronomer Eugene Magnier, used the 10-meter Keck II and Pan-STARRS1 telescopes in Hawai‘i to find a star that breaks the galactic speed record. It travels at about 1,200 kilometers per second (about 2.7 million mph), a speed that will enable the star to escape from our Milky Way galaxy. “At that speed, you could travel from Earth to the moon in 5 minutes,” Magnier commented. The team showed that unlike the half-dozen other known escaping stars, this compact star was ejected from an extremely tight binary by a thermonuclear supernova explosion. Stars like the Sun are bound to our galaxy by its gravity and orbit its center at relatively moderate velocities, tens to a few hundreds of kilometers per second. Only a few so-called hypervelocity stars are known that travel so fast that they are unbound. A close encounter with the supermassive black hole at the center of the Milky Way is usually considered the most plausible mechanism for enabling these stars to escape from the galaxy. Stephan Geier (European Southern Observatory, Garching, Germany) led the team that observed the known high-velocity star, US 708, with the Keck II telescope to measure its distance and radial velocity component, that is, how fast it is moving away from us. By carefully combining position measurements from digital archives with newer positions measured from images taken during the Pan-STARRS1 survey, they were also able to derive the tangential component of the star’s velocity, or how fast it is moving perpendicular to us. “By observing the sky repeatedly over several years, the Pan-STARRS1 survey let us make a movie of the motions of the stars in the sky. That enables us to study the behaviors of extremely rare and weird stars like US708,” Magnier explained. By putting all the measurements together, they determined the total velocity of the star is 1,200 kilometers per second, much higher than the velocities of the other known stars in our galaxy. More importantly, the trajectory of US 708 allows them to rule out the Galactic Center, and therefore, its supermassive black hole, as the possible cause of US 708’s extreme velocity. US 708 has additional peculiar properties that are in marked contrast to other hypervelocity stars: it is a rapidly rotating, compact helium star that probably formed as a result of interaction with a close companion. Helium stars are the remnant of a formerly massive star that has lost its hydrogen envelope. Thus, US 708 could have originally been part of an ultracompact binary system in which it transferred helium to a massive white dwarf companion, ultimately triggering a thermonuclear explosion known as a type Ia supernova. As a result of this explosion, the surviving companion, US 708, was violently ejected from the disrupted binary, and is now traveling at an extremely high velocity. These results provide observational evidence that there is a link between helium stars and thermonuclear supernovae, and are a step toward understanding the progenitor systems of these mysterious explosions. Artist’s conception of a star (left) being ejected from a galaxy by a supernova explosion. In reality, the supernova would have been faded away long before the star reached that position. Art courtesy of ESA/Hubble, NASA. 5 Astrobiology Researcher Finds New Microbes Two miles below the surface of the ocean, researchers have discovered new microbes that “breathe” sulfate. The microbes, which have yet to be classified and named, exist in massive undersea aquifers—networks of channels in porous rock beneath the ocean where water continually churns. About one-third of Earth’s biomass is thought to exist in this largely uncharted environment. “It was surprising to find new bugs, but when we go to warmer, relatively old and isolated fluids, we find a unique microbial community,” said Alberto Robador, the lead author of the paper on the findings who began the project while he was a UH NASA Astrobiology Institute (NAI) postdoctoral fellow. “Finding diverse microbial life here on Earth helps us understand what kinds of life may exist elsewhere in our solar system and on planets orbiting other stars,” explained IfA astronomer Karen Meech, the head of UH NAI. Sulfate is a compound of sulfur and oxygen that occurs naturally in seawater. It is used commercially in everything from car batteries to bath salts and can be aerosolized by the burning of fossil fuels, increasing the acidity of the atmosphere. This graphic shows the innovative technology that allowed the scientists to collect samples of water from an aquifer two miles below the ocean without contaminating the samples with ocean water. Credit: Courtesy of USC Microbes that breathe sulfate—that is, gain energy by reacting sulfate with organic (carbon-containing) compounds—are thought to be some of the oldest types of organisms on Earth. Other species of sulfate-breathing microbes can be found in marshes and hydrothermal vents. Researchers from UH and the University of Southern California took their samples from the Juan de Fuca Ridge (off the coast of Washington state), where previous teams had placed underwater laboratories, drilled into the ocean floor. To place the labs, they lowered a drill through two miles of ocean and bored through several hundred feet of ocean sediment and into the rock where the aquifer flows. Like the microbes on the forest floor that break down leaf litter and dead organisms, the microbes in the ocean also break down organic (carbon-based) material such as dead fish and algae. Unlike their counterparts, however, the microbes beneath the ocean crust often lack the oxygen that is used on land to effect the necessary chemical reaction. Instead, these microbes can use sulfate to break down carbon from decaying biological material that sinks to the sea bottom and makes its way into the crustal aquifer, producing carbon dioxide. Learning how these new microbes function will be important to getting a more accurate, quantified understanding of the overall global carbon cycle—a natural cycling of carbon through the environment in which it is consumed by plants, exhaled by animals and enters the ocean via the atmosphere. This cycle is currently being disrupted by man-made carbon dioxide emissions. “This is the first direct account of microbial activity in these type of environments, and shows the potential of these organisms to respire organic carbon,” said Robador, who is now a postdoctoral research associate at USC’s Center for Dark Energy Biosphere Investigations (C-DEBI). HI STAR Students Succeed at Maui, State Science Fairs For the third consecutive year students who have participated in IfA’s HI STAR program took top honors at the Maui County Science and Engineering Fair. HI STAR, or Hawai‘i Student/Teacher Astronomy Research, is an IfA program that encourages middle and high school students to excel in the sciences by teaching them how to do astronomical research. Sarah Jenkins and Lily Jenkins (Moloka‘i High School) won the first place award for a project that studied mangroves. Luke Jones (Kihei Charter School) won a merit award, an award for mathematics, and an award for “most technical and complete” for his project on modified Newtonian dynamics that used data from the Las Cumbres Observatory Global Telescope (LCOGT) network and the Pan-STARRS telescope on Maui. Both of these projects advanced to the state level. Celeste Jongeneelen (home schooled) also won a merit award and advanced to the state level. Her project on identifying Ae/Be stars in young open clusters is the first high school project that used the FLOYDS spectrograph on the LCOGT 2.0-meter telescope network. Christopher Kim and M. Thomas Sturm, who won third place for Physics and Astronomy at last year’s Intel International Science and Engineering Fair (ISEF), took this year’s project, which studied the differences in helioseismic results using different spectral lines, to the state level competition. So how did these students do at the state level? Luke Jones won second place overall, first place for physics and astronomy, and first place among Hawai’i public schools. He will be attending ISEF in May. Celeste Jongeneelen won third place for physics and astronomy, the Hawaiian astronomical award, and an award from NASA. Christopher Kim and Thomas Sturm won an award from the American Public Works Association. HI STAR participants and parents at the state science fair. Back row from left to right: Tracy Jones and her son Luke Jones, Lily Jenkins, Celeste Jongeneelen and her mom, Esther Pollock-Jongeneelen, Christopher Lindsay, Kayla Ishida, Christopher Kim, and M. Thomas Sturm. Front Row: Sarah Jenkins and Hedi Jenkins (mother of Sarah and Lily) with HI STAR director Mary Kadooka. Photo courtesy J. D. Armstrong. In addition, HI STAR participants from O‘ahu, Lelani Gamboa and Christopher Lindsay, also won awards at the state fair, and Kayla Ishida came from Kaua‘i. There were nine astronomy projects at the state fair. J. D. Armstrong, IfA’s Maui Technology Education and Outreach Specialist, mentored three of them (with IfA alumnus Marco Micheli, in the case of Luke Jones), and Katie Whitman (IfA alumna and current physics graduate assistant), Larry Denneau (senior software engineer for IfA’s ATLAS project), and Geoff Mathews (IfA alumnus and current astronomy instructor) each mentored one. Unfortunately, there will be no HI STAR program in 2015 because funding has lapsed. IfA staff who worked on this very successful program hope to obtain funding so that they can restart it in 2016. 7 From the Director The JCMT handover signing. Back row: Jun Yan, director, National Astronomical Observatories of China; IfA Director Günther Hasinger; Gary Davis, former director, Joint Astronomy Centre. Front row: Paul Ho, director general, East Asian Observatory; Matt Platz , assistant chancellor for academic affairs, UH; John Womersley, chief executive STFC. Credit: Hollyn Johnson/Gary Davis/STFC. Nā Kilo Hōkū “The Ones Who Look to the Stars” No. 53 • 2015 Published by The University of Hawai‘i Institute for Astronomy www.ifa.hawaii.edu Günther Hasinger IfA Director Louise H. Good Editor Karen Teramura Design/Production Roy Gal Education & Outreach TE FOR AS T RO NOMY INSTITU Nā Kilo Hōkū is also online: www2.ifa.hawaii.edu/newsletters/ i ‘i U ni ve wa rsit y of Ha On March 1, the University of Hawai‘i assumed ownership of the James Clerk Maxwell Telescope (JCMT) located on Maunakea. It was formerly owned by the Science and Technologies Facilities Council (STFC) of the United Kingdom. Simultaneously, the operation of JCMT was assumed by the East Asian Observatory (EAO), a consortium of astronomy agencies in China, Japan, South Korea, and Taiwan, under a scientific cooperation agreement with UH. JCMT will continue to be operated from the Joint Astronomy Centre Building in Hilo by most of the same personnel. Dr. Paul Ho, former director of Taiwan’s Academia Sinica Institute of Astronomy and Astrophysics and now director general of EAO, now heads the JCMT. UH Institute for Astronomy 2680 Woodlawn Drive Honolulu, HI 96822-1839 This new arrangement is similar to the one developed for the United Kingdom Infrared Telescope (UKIRT). UH assumed ownership of that telescope on October 31, 2014, and negotiated a scientific cooperation agreement with the University of Arizona and Lockheed Martin Space Technology Advanced Research and Development Laboratories to provide for UKIRT’s continued scientific operation. Though both UKIRT and JCMT have been very successful scientifically, STFC announced in 2012 that it no longer had the funds to support them. UH will continue to receive a guaranteed share of the observing time on both telescopes. We at IfA are glad that we have been able to make arrangements to keep these valuable telescopes operating. Please join us for the annual IfA Mānoa Open House on April 12.