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SUPARCO - ASTRONOMY & ASTROPHYSICS BULLETIN Volume I, Issue 6 Pakistan Space Vision 2040, was approved by the Prime Minister of Pakistan which inter-alia included augmentation / strengthening of the Astronomy and Astrophysics programmes of SUPARCO. SUPARCO`s astronomy and astrophysics program is mainly focused on theoretical and observation research. For this an astronomical observatory is planned to be established. Research studies pertaining to deep space objects including galaxies, nebulae and variable stars are also being initiated. Search for earth like planets is a hot topic in astrophysics nowadays. It is planned to conduct research studies in this field also. Inside this Issue: The phenomenon of Transit Red Giant Stars Book Review The Phenomenon of Transit Transits are among the events which are observed with interest by astronomical community all over the world. Transit means the passage of one astronomical body (smaller in apparent size) across the face of another astronomical body (bigger apparent diameter), shadowing a portion as seen by an observer from a vantage point in space. Another meaning of transit is the crossing of an astronomical object over the meridian of the observer. The most common transits occuring every month are the satellites (moons) of Jupiter and Saturn passing over the faces of the planets as seen from the Earth. The picture to the right shows one of such a transit of Io, Jupiter’s moon. Io can be spotted at the center of the image whereas its shadow can be seen on the dense, cloudy atmosphere of Jupiter. Sometimes there are transits of man-made objects across the faces of astronomical bodies including the Sun and the Moon, especially. Amateur astronomers are very Transit of Io over Jupiter. the keen in observing and photographing such shadow of Io can also be seen on the cloudy surface of Jupiter rare events. Such events last only for few seconds and thus require high level of expertise in telescope and camera operation to catch the glimpses of a satellite passing over the face of an object. Ecliptic This remarkable picture taken by an amateur astronomer showing the partial solar eclipse of 4th January 2010 along with the transit of the International Space Station (ISS), in an orbit around the Earth. A sunspot at the lower right limb on the solar disk can also be seen. Sky this Month Web Review Software Review Addional Ionozation by Meteor Shower Meteorite found in Tharparker Pass of ISS over Sun during partial solar eclipse of Jaunary 4, 2012 9 Events of the Month Date Time 06 Jun After Sunrise Before Sunrise 17 Jun 20 Jun 21 Jun 27 Jun - June, 2012 Event\Direction Transit of Venus\ East Moon, Jupiter, Venus\ East June Solstice After Sunset New moon, Mercury, Castor and Pollux After Sunset Mars, Saturn & Quarter moon Transit of Venus SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication The inferior planets, Venus and Mercury, accordingly are the planets for which we see transits. However, as seen from outer planets such as Mars, Jupiter etc, the Earth itself transits the Sun. While transits of Mercury are relatively common, occurring once or twice every decade, the transits of Venus are extremely rare, occurring less than twice a century. The first ever observed transit of Venus was in 1639, and since then, only 5 transits of Venus have occurred, the last one in 2004. Page II The next transit of Venus occurs June 6, 2012, and then not again until 2117. On 13th November 1986, there was a transit of Mercury at the solar disc as seen from Earth at 0745 hours (PST) and continued its apparent travel until 1130 hours (PST). SUPARCO scientists tracked its path over the solar disc and captured a series of photographs of this event. Astronomical Unit today, but it is instructive to learn how the old methods worked. A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and the Earth, becoming visible against the solar disk. During a transit, Venus can be seen as a small black disk moving across the face of the Sun. The duration of such transits is usually measured in hours. A transit is similar to a solar eclipse by the Moon. While the diameter of Venus is almost four times that of the Moon, Venus appears smaller, and travels more slowly across the face of the Sun, because it is much farther away from Earth. Observations of transits of Venus helped scientists use the principle of parallax to calculate the distance between the Sun and the Earth. The principal events occurring during a transit are characterized by four contacts. The event begins with contact I which is the instant when the planet's disk is externally tangent with the Sun. The entire disk of the Venus is first seen at contact II when the planet is internally tangent with the Sun. During the next Transit of Mercury , November 1986 as observed by several hours, Venus gradually traverses the solar SUPARCO disk at a relative angular rate of approximately 4 In June 2004, first of the pair of transits of Venus for arc-min/hr. At contact III, the planet reaches the 21st century occured. This transit of Venus was opposite limb and is once again internally tangent with observed by the scientist to refine their techniques to the Sun. The transit 2005 Annular ends atSolaco contact IV when the search for extrasolar planets. planet's limb is externally tangent to the Sun. Contacts I and II define the phase called ingress while contacts III and IV are known as egress. Greatest transit is the instant of minimum angular separation between Venus and the Sun as seen from Earth's geocenter. Transit of Venus on June 8, 2008; the first of the pair for 21st century Despite being so rare, transits of Venus have played an important role in the history of astronomy. Many governments organized elaborate and expensive expeditions to remote parts of the globe so that astronomers could view the transit from several different sites during Venus transit of 1761, 1769, 1874 and 1882. The main reason for such interest was that transits of Venus provided a unique opportunity to determine the length of the Astronomical Unit, which is the average distance between the Earth and the Sun, a fundamental scale in the universe. We have easier and more precise methods of determining the SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication Event Universal Time Position Angle Contact I 22:09:38 41° Contact II 22:27:34 38° Greatest 01:29:36 345° Contact III 04:31:39 293° Contact IV 04:49:35 290° Contact timings for transit of Venus 2012 Visibility of 2012 transit of Venus The entire transit (all four contacts) is visible from northwestern North America, Hawaii, the western Pacific, northern Asia, Japan, Korea, eastern China, Philippines, eastern Australia, and New Zealand. The Sun sets while the transit is still in progress from most of North America, the Caribbean, and northwest South America. Similarly, the transit is already in progress at sunrise for observers in central Asia, the Middle East, Europe, and eastern Africa. However the transit will not be visible from Portugal or southern Spain, western Africa, and the southeastern 2/3 of South America. Page III 2012 Transit of Venus in Pakistan: The sunrise timing for 6th June for Karachi is 05:44 PST. By this time, Contact I and Contact II of transit of Venus will already have been passed and Venus would be close to its minimum angular separation with the Sun, an event that will occur at 06:29:36 PST. Contact III would occur at 09:31:39 PST when Venus would be tangent to the other limb of the Sun and the last contact will at 09:49:35 AM when Venus will be at the outer tangent to the surface of Sun. Transit of Venus; Just after Sunrise Contact III Contact IV SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication Don't Miss the Transit of Venus in 2012: It's Your Last Chance Until 2117 As the 6th June is coming near, people around the world are preparing for this last in a lifetimes event. Astronomers are travelling to the sites where the visibility of transit would be the best. Scientific organizations are arranging different public gathering for promoting astronomy using this event. Some are even preparing to broadcast the event for general public. What are other ways through which public can witness this celestial event? Eclipse shades and sunlight filters can be use to safely view the sun. But since the diameter of Venus would be around one arc min, it would be difficult to observe it with eyes. The better options are using magnifier with filters. Back view projection technique can also be used to project the image of the sun onto a white screen with the people gathering around the screen watching the transit. In this era of technological revolution, for those places where transit would not be visible entirely or there are no means of observing the transit, an iphone application of transit of Venus is now available that can be used to observe transit at your palm. This application has been designed to inspire international collaboration during the 2012 transit of Venus by enabling a digital re-creation of those global expeditions. The phone app will allow citizens around the world to witness this rare phenomenon and to contribute their observation to a collective experiment to measure the sun’s distance. To have extended utility, the phone app will serve before, during, and after the transit. Prior to the transit, one can practice timing the interior contacts using a simulation of the transit. Additionally, one can see predicted times of contact for one’s location. During the transit, the phone app will assist in measuring the time of the interior contacts. This application can be downloaded from www.transitofVenus.org The last time pair of transit of Venus occurred on Dec 09, 1874 and Dec 06, 1882. At this time no one had ever imagined that by the next pair of transit of Venus people would be using much sophisticated ways and technology for viewing transit of Venus. By the end of this transit of Venus, humanity would have to wait more than 105 years to witness another transit of Venus and who knows at that time what revolutions would have occurred in science and technology. Page IV Red Giant Stars Red giant is evolved by converting most of its hydrogen to helium by thermonuclear fusion. Red giant is greater luminosity star and has a diameter of 10 to 100 times the Sun with surface temperature below about 4000 K. Internal Composition of Red Giant Star HR diagram illustrating the evolution of stars into different final stages Formation of red giant star In the beginning, stars generate energy fusing hydrogen atoms into helium by thermonuclear fusion process. The process of fusing hydrogen into helium continues for billions of years and eventually exhaust the hydrogen at the core of a star. In the absence of energy flowing out from a star to counterbalance the inward force of gravity, the core collapses and the hydrogen that remains in a shell around the core of star begins to burn and causes increase in luminosity of star. As core collapses, the outer atmosphere layers of star expand outward. This expansion cools the surface layers turning star it into red giant. The expansion of outer layers of star drops its surface temperature and extends star radius tens to hundreds times larger than radius of the Sun. Meanwhile, the temperature in the collapsing core ascends, becoming hot enough in some stars to start fusing the helium atoms into carbon and carbon into other heavier elements. This can only happen in stars comparable in mass to the Sun and greater; less massive stars cannot become hot enough in their cores of begin fusing helium, and they eventually fade out when their last reserves of hydrogen and helium exhausted. SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication The stars having mass 10 to 70 solar mass during their red giant phase become “red supergiants”. Red supergiant stars may have luminosity million times greater than the Sun. These are very massive stars seen just before their supernova stages. Betelgeuse, Antares and Arcturus are the best examples. Betelgeuse Red Supergiant Star (Constellation Orion) There are stars which do not enter red giant phase are called Red dwarf stars having mass less than 0.35 solar mass. They transport energy from center to surface through convectional process, mixing helium produced at their cores throughout the rest of their bodies. As a result, these stars do not gather an inert core of helium and are predicted to exhaust all of their hydrogen fuel without ever becoming red giants. The Page V Book Review expected lifetime of these stars is much greater than the current age of the universe. Fate of Sun as a Red Giant: Unlike the other heavier stars, the Sun does not possess enough mass to explode as a supernova. The sun has passed about half of its life period. In about 5 billion years, it will enter a red giant phase. Its outer layers will expand as the hydrogen fuel at the core is exhausted and the core will contract and heat up. Hydrogen burning will continue in a shell surrounding helium core, which will gradually expand as more helium is produced. The surface temperature of the Sun would reduced as outer layers of the Sun expands. The hydrogen burning shell will increase the Sun luminosity and Sun will become red giant star. The sun would be up to 250 times its current size due to its outer layers expansion, as big as 1.4 AU and will swallow up the Mercury, Venus, Mars and the Earth. Finally when the core temperature reaches around 100 million Kelvin’s, helium fusion at the core will begin producing carbon and oxygen. The intense thermal pulsations will cause the Sun to throw off its outer layers, forming a planetary nebula around degenerate dense carbon and oxygen core which is then called White Dwarf. SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication There is nothing more satisfying than making a telescope and using it to observe the star-studded sky. As the name of the book suggests, Making and Enjoying Telescopes, is surely a gift and worth an asset for enthusiasts and amateur astronomers alike. Written by Robert Miller and Kenneth Wilson, the book contains eight chapters giving information from the history of telescopes to amateur telescope makers. Along with these chapters, there are six complete projects for building small telescope up to 10 inch diameter (Primary Mirror). Not only reflectors are shown how to build but also one of the very famous design amongst amateurs i.e. the Dobsonian Mount 10 inch telescope is featured. Appendices contain some technical information about correct placement of diagonal mirror (secondary mirror) and some basic formulae necessary to use in telescope construction. Those university students who are undertaking a project may find this book as an important source, if they choose to build a telescope. Page VI Sky this Month June 4, 2012 - Full Moon Earth will be between the Sun and Moon, and therefore, the Moon will be fully illuminated as seen from Earth. This phase takes place at 11:12 p.m. UT. June 05, 06, 2012-Venus transiting the Sun This rare event will be entirely visible mostly in East Asia, eastern Australia and Alaska. A partial transit can also be seen in progress at sunrise throughout Europe, West Asia and East Africa. A partial transit can be seen in progress at sunset in most of North America, Central America, South and West America. It will not take place again until 2117. June 17, 2012- Moon, Jupiter, Venus and Pleiades Cluster at Dawn This congregation of the two planets, Jupiter and Venus, moon at the edge of being new moon and visually appearing an open cluster of seven stars called Pleiades would be visible at around dawn on June 17. This view will be visible in the eastward direction, but being close to horizon, observers may have some difficulties in spotting the objects. Very close to horizon a reddish color star called Aldebran in constellation Taurus and a bluish white star Capella can also be observed in the same direction. SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication June 20, 2012 - June Solstice June solstice occurs at 23:09 UT. North Pole of the Earth will be tilted towards the Sun, which will reach the northernmost position in the sky. This is the first day of summer (summer solstice) on the northern hemisphere, and the first day of winter (winter solstice), in the southern hemisphere. June 21, 2012- New moon, Mercury, Castor and Pollux at dusk At the dusk of June 21, a kind of sinusoidal shape can be seen made by the objects including Procyon, a yellowish star; then new moon; then Mercury and finally then Pollux and Castor, the two brightest stars of constellation Gemini. This view would be visible in the West direction. June 22, 2012 - New Moon Moon will be directly between Earth and Sun and will not be visible from Earth. This phase takes place at 15:02 UT. June 27, 2012- Mars, Saturn and the quarter moon At the 8:00 PM local timings on June 27, Saturn and the Mars would have their appearance in the southern sky with quarter moon nearly in between these two planets. It would be a nice show of colors in the night sky with Saturn appearing yellowish then moon with its glittering white light and then Mars, strongly reddish in its appearance. Page VII Web Review Software Review HubbleSite is a truly a wonderful website providing various services at the same time all that related to Hubble Space telescope. Bringing the magnificent images from the Hubble Space Telescope (HST) back down to Earth, HubbleSite is the place for all things. The NewsCenter service provides updated information about what’s going on with Hubble Telescope and other astronomical news as well. Apart from this, one can also find information about the discoveries of HST or just learn more about the telescope itself. HST all time masterpieces are also there for viewing and the site goes all-out with the images. One can also download wallpaper, watch videos in the movie theater, and take image tours. It’s all available in the gallery section. Starry Night is planetarium software with realistic imagery and real time appearance of the sky and other astronomical phenomenon including past and future appearance of object in the sky. Initially developed by Sienna Software, Starry Night now owned and developed by Simulation Curriculum Corp. this software is available for both Macintosh and PC(Windows) operating system. An iPhone application of Starry Night is also available although the recent versions of the software specially target the amateur community with features like observation planning, telescope control and multiple-panel printing. Starry night is using the Hipparacos Catalogue, the Tycho-2 Catalogue, and the Tully catalogue of galaxies for its data base. It has options of viewing the night sky from any location on Earth or viewing the Earth from any location of the solar system or even viewing the Milky Way and other nearby galaxies. Time lapse can be made fast or slow at your own convenience. One can also calculate ephemerides of solar system objects, generating Hertzsprung-Russell diagram of stars and also displaying current imagery of solar and Earth observing Satellites. The software can also be interfaced with laptops and computers, using GOTO telescopes through this software. Starry Night has different versions, available right now, from a beginner to a student version and from astronomy enthusiast to advanced amateur astronomy version. Although a commercial software, Starry Night can be a wonderful beginning for those who are enthusiastic about astronomy. SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication Page VIII Additional Iononization by Meteor Shower in the Ionosphere Our Earth is surrounded by several gases and water vapours which make the life possible on the Earth. The atmosphere of the Earth has different layers depending upon the concentration of air molecules, altitude, temperature, pressure and other parameters. These layers are troposphere, stratosphere, mesosphere, thermosphere and exosphere. All these layers have been defined in the neutral atmosphere; however, the upper atmospheric layers get ionized due to the solar extreme ultraviolet radiation and x-rays. This ionized region is called ionosphere which ranges from 60km – 1000km in altitude. This is where free electrons and ionized molecules are found and these electrons support the long range radio communication over the entire globe. The ionosphere is further divided into designated regions as D, E, and F. The D and E-layers both disappear at local night due to the absence of sun whereas F is a 24/7 existing layer. SUPARCO being the national space agency of Pakistan monitors the behaviour of ionosphere using three monitoring stations, one each at Sonmiani, Multan and Islamabad. The instrument used for the purpose is called digisonde which is basically a radar system. Earth’s Atmospheric layers There is a special layer of the ionosphere which is present in the E-region and is called the sporadic E layer or ‘Es’. It may occur any time of the day at an altitude of about 100km. The lifetime of the sporadic E depends upon the latitude and it can last from a few minutes to several hours. Long range communication can be possible due to this highly ionized cloud but it is unreliable as the existence of sporadic E is not guaranteed throughout the day. One of the several causes of formation of Es is a meteor shower. Meteorites are generally composed of metallic ions which play an important role is ionizing the E-layer and uneven patches of excessive ions form randomly at the time of meteor shower. Strong existence of Es was observed at Multan during night of 4th & 5th May 2012. This was the time when Eta Aquarids occurred on the full moon night. Eta Aquarids is one of the well defined meteor showers associated with Halley’s Comet. On the same night a meteorite was found in Tharparkar district as mentioned in this bulletin. The figure shows an ionogram (output of digisonde) which is a frequency in MHz (x-axis) versus height in km (y-axis) profile of the local ionosphere monitored at Multan during the mentioned night. The horizontal coloured pattern at 100km shows the existence of the sporadic E layer. Es layer observed at Multan on the night of May, 4 2012 SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication Page IX Meteorite found in Tharparker On the midnight of May 4, 2012, the time when Eta Equarids meteor shower was at its peak, a meteorite was reported to have fallen in a village of Tharparker, called Ladki. It was a small meteorite weighing around 100 grams. The meteorite was then transferred to a nearby small city called Diplo where its news was broken by a local newspaper. Later on, this meteorite was formally handed over to a team of SUPARCO officials. A search in nearby areas where the meteorite was reported to have fallen was also undertaken by SUPARCO researchers to recover any other pieces, but none were found. Facts about Meteorite: Small crater produced by the Meteorite Falling The piece of the meteorite handed over to SUPARCO weights 73 grams with density 3.51 grams/ml. The miniral content ofthe meteorite were Iron, Nickel, Cobalt, Zinc. Iron is found to have the largest percentage of all constituent particles which is 11%. That means out of 73grams, 8 grams is the Iron contents making meteorite magnetic and susceptible to magnetic materials. Although an extensive research is still need to be done in which meteorite class would be found that will ultimately suggest its name according to international standards. This research would also recognize this recovery of meteorite in Pakistan according to the rules of Institute of Meteoritic (IOM) and International Meteoritical Society (IMS). Meteorite found in Tharparkar Schematic diagram illustrates the formation of the classic strewn field. When a meteoroid enters the upper atmosphere along an inclined trajectory, great decelerating forces usually cause it to break into tens, hundreds, or even thousands of pieces. The smaller pieces slow down more quickly than the larger pieces. When they hit the ground they distribute themselves within an elongated ellipse with the smaller pieces at the near end and the larger heavier pieces at the far end. Crosswinds can severely alter this pattern. Contact Information A metallic or rocky small body orbiting the sun in space; small particles that may derive from comets; larger (1 cm or larger) particles that probably derive from the asteroid belt. Meteoroids seen passing through an atmosphere are called meteors, and if they survive to land on the surface, they are called meteorites. Small meteoroids are also often called interplanetary dust particles (IDPs). Sunlight reflecting off this material gives rise to the zodiacal light. Rizla Zareen General Manager Gulzar-e-Hijri SUPARCO Road Sector 28, SUPARCO, Karachi, Pakistan Tel: 021-34690765-74 Fax 021-34690795 Email: [email protected] SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication This bulliten can be downloaded from the official website of SUPARCO