Volume I, Issue 10 October, 2012

SUPARCO - ASTRONOMY & ASTROPHYSICS

Pakistan’s 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 observational 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.

Events of the MonthDate Time Event\Direction

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BULLETIN

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New Moon15 Oct

Oionid Meteor Shower21-22 Oct

Full Moon29 Oct

Inside this Issue:

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Mercury conjuct Saturn

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Perhaps the most striking characteristic of the solar system is the obvious division of the planets into two groups: the small Earthlike planets and the giant Jupiter-like planets. The two kinds of planets are distinguished by their locations and masses. The four inner Terrestrial planets are quite different from the four outer Jovian planets. Craters are common. Almost every solid surface in the solar system is covered with craters. The two groups of planets are also distinguished by properties such as presence or absence of rings and numbers of moon.

Starting from the Sun, the first planet to be encountered is Mercury. It is the closest planet to the sun and also lies within the orbit of the Earth hence very difficult to observe. It is always observed very low in the eastern or western direction during twilight conditions. It fairly resembles our moon in appearance with size half of the diameter of the Earth. The temperature variation is so immense that it is impossible for any kind of life to be developed on the Mercury. The proximity of the Sun made its days very hot whereas during nighttime the temperature falls way below the freezing point. Mercury has the shortest orbital period of all the planets, 88 Earth days, whereas it spins on its axis every 58 days and 14 (Earth) hours.

The Terrestrial Planets; Mercury:

MercuryObservation:Of the five planets visible to the naked eye, Mercury is the most difficult to spot because it remains close to the Sun. The best time to observe Mercury is when it lies at its greatest elongation, such as when it is farthest from the Sun. At that time with magnification more than 200, Mercury will appear as large as full moon to naked eye. Mercury can also be observed in phases like moon and Venus.

The Terrestrial Planets: Mercury 1

Comets 3

Web Review 4

Monthly Star Guide: October 5

Book Review 6

Software Review 6

Sky t his Month 7

Astronomy News Update 7

Understanding Space Weather 8

Geomagnetic Feild monitoring by SUPARCO 9 Observation of binary Stars 10

AfterSunset

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Atmosphere and Climate:There is no air and water on Mercury. The hard rocky surface is scorched by the Sun raising its temperature more than 450 ˚C at equator and during nighttime the temperature goes below -290˚C. Some ice is assumed to be found at its polar regions which remained shaded.

Carters:As on the Moon, the youngest craters on Mercury are bright and surrounded by rays of material ejected by the force of the meteorite impact. Mercury has one large lowland plain, the Caloris Basin, which resembles the mare areas of the moon. There are no known volcanic craters on Mercury.

This composite image of the Caloris basin was created with pictures from Mariner 10 (right portion) and

MESSENGER images. Schemetic view of Inner layers of Mercury

Geography and Geology:Mercury looks much like our Moon, since the rocky surfaces of the both bodies have been extensively cratered by the impacts from meteorites. Also Mercury’s diameter is 40 percent larger than our Moon. One distinct difference between Mercury and Moon is that Mercury has cliffs 2 miles high. Mercury is thought to have a large iron core that occupies three-quarters of its diameter.

A close-up view of Caloris basin

Mercury with Caloris basin circled

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The word Comet is a Latin word which means “long haired star”. They are made out of dust and ice like a dirty snow ball. They are the members of solar system. Comets are small, fragile, irregularly shaped bodies composed of a mixture of non-volatile grains and frozen gases. They have highly elliptical orbits that bring them very close to the Sun and swing them deeply into space, often beyond the orbit of Pluto. Comets structure is diverse and very dynamic, but they all develop a surrounding cloud of diffuse material, called a coma, that usually grows in size and brightness as the comet approaches the Sun. Usually a small, bright nucleus (less than 10 km in diameter) is visible in the middle of the coma. The coma and the nucleus together constitute the head of the comet.

Comet Hyakutake

Comets

As comets approach the Sun they develop enormous tails of luminous material that extend for millions of kilometers from the head, away from the Sun. When far from the Sun, the nucleus is very cold and its material is frozen solid within the nucleus. In this state comets are sometimes referred to as a "dirty iceberg" or "dirty snowball," since over half of their material is ice. When a comet approaches within a few AU of the Sun, the surface of the nucleus begins to warm, and volatiles evaporate. The evaporated molecules boil off and carry small solid particles with them, forming the comet's coma of gas and dust.

This image of comet C/2001 Q4 (NEAT) was taken by the WIYN 0.9-meter telescope at Kitt Peak National Observatory near Tucson, Arizona, on May 7, 2004.

This color photograph of the comet Kohoutec was taken by members of the lunar and planetary laboratory photographic team from the University of Arizona. They photographed the comet from the Catalina observatory with a 35mm camera on January 11, 1974.

The Hubble Space Telescope images of comet Hyakutake on the right were taken on March 25, 1996 when the comet passed at a distance of 9.3 million miles from Earth. These images focus on a very small region near the heart of the comet, the icy, solid nucleus and provide an exceptionally clear view of the near-nucleus region of the comet.

Comet Neat

Comet Kohoutek

Book Review

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Web Review

The website under review for this month is www.galaxyzoo.org. Roughly one hundred billion galaxies are scattered throughout our observable Universe, each one is a glorious system that might contain billions of stars. Many are remarkably beautiful, and the aim of Galaxy Zoo is to study them, assisting astronomers in attempting to understand how the galaxies we see around us, formed, and what their stories can tell us about the past, present and future of our Universe as a whole.

This website was started back in July 2007, with a data set made up of a million galaxies imaged by the Sloan Digital Sky Survey, which still provides some of the images in the site today. With so many galaxies, we'd assumed it would take years for visitors to the site to work through them all, but within 24 hours of launch we were stunned to be receiving almost 70,000 classifications an hour. In the end, more than 50 million classifications were received by the project during its first year, contributed by more than 150,000 people.

For the month of October, our nearest galaxy, Andromeda, lies at overhead for the observers in Northern Latitudes, whereas for Southern Latitudes it lies relatively low, not offering good views. There are few bright stars on the display at this time of the year, but the Great Square of Pegasus is easy to see from both hemispheres.

Northern Latitude:•Looking North:The Milky Way arches overhead from west to east. Cassiopeia is high up, above and to the left of Perseus constellation. Capella and the other stars of Auriga are rising in the northeast along with Taurus. This is sometimes used and a foretaste of winter. The Summer Triangle can still be seen in the west, with Altair lying in the southwestern sky.•Looking South:High in the south, the Great Square of Pegasus is well placed with Andromeda above and to its left. Pices lies to the left of Pegasus, and Aquarius is to its lower right. Low in the south is Fomalhaute with Cetus in the southern sky.

Monthly Star Guide: October

The Great Square of Pegasus

Sky this Month

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Book Review

Dickinson is perhaps the leading writer of English-language amateur astronomy books; his Nightwatch is rightly considered one of the best introductions to the night sky and how to Terence observe it. It covers the broad range of amateur astronomy admirably, from science to equipment to observing tactics. One of the only glaring drawbacks to the book is that it is simply too short.

The Backyard Astronomer's Guide is an able sequel. Written with fellow Canadian amateur Alan Dyer, it goes further in depth than does Nightwatch. Because it also goes into specifics in recommending telescopes and accessories, however, it quickly grew out of date. A somewhat updated and revised edition came out in 1994, but more than eight years have passed since then, and most of the models described there have been discontinued, although a few of them have continued to the present day.

Now, at last, this book is available in a true second edition. The changes are at once obvious and subtle. Obvious, in that the production is stunning: the old photos, mostly black-and-white, have been replaced by beautiful full-color images of the night sky and detailed diagrams of equipment. Subtle, in that the table of contents reads almost the same; it's not so much the inherent content that has changed so much as how it's presented.

One chapter from the first edition that has disappeared is one entitled "Ten Myths About Telescopes and Observing." In the first edition, this chapter was praised by reviewers and readers alike (and excoriated by some other readers, too!); it undoubtedly surpassed Dickinson and Dyer's expectations in terms of the amount of discussion it engendered. Whether you agree with them or not, they have at least educated their readers about the dispute over these myths.

Software Review

Nightshade is free, open source astronomy simulation and visualization software for teaching and exploring astronomy, Earth science, and related topics. It is the only truly open dome projection simulator designed specifically for the planetarium community.

Nightshade was a fork of the award-winning Stellarium software, but tailored for planetarium and educator use. Nightshade 12, currently in development, will be a complete rewrite, removing current limitations in favor of open simulation industry standards.

It is available for Linux, Windows, Mac OSX, and other platforms.

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October 5, 2012 - Mercury conjuncts Saturn: Mercury and Saturn will be in conjunction.

October 15, 2012 - New Moon: Moon will be directly between Earth and Sun and will not be visible from Earth. This phase takes place at 12:02 UT.

October 21-22, 2012 - Orionide meteor shower: Orionids are a meteor shower of medium intensity, which produces about 20 meteors per hour. A good view is in any morning from October 20 to 24. The first Quarter Moon will set before midnight, leaving a dark sky. The best cardinal point to see will be to the east after midnight. Orionids originates from Comet Halley.

October 29, 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 19:49 UT.

Astronomy News Up DateSky this MonthScientists Shed Light On Riddle of Sun's Explosive EventsFour decades of active research and debate by the solar physics community have failed to bring consensus on what drives the sun's powerful coronal mass ejections (CMEs) that can have profound "space weather" effects on Earth-based power grids and satellites in near-Earth geospace.

Nobel Prize in Physics 2012: Particle Control in a Quantum WorldThe Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2012 to Serge Haroche Collège de France and Ecole Normale Supérieure, Paris, France and David J. Wineland National Institute of Standards and Technology (NIST) and University of Colorado Boulder "for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems."

Bringing the Inertia of Space to Robotics ResearchThe U.S. Naval Research Laboratory Spacecraft Engineering Department's space robotics research facility recently took possession of a one-of-a-kind 75,000 pound Gravity Offset Table (GOT) made from a single slab of solid granite.

Hubble Discovers a Fifth Moon Orbiting PlutoA team of astronomers using NASA's Hubble Space Telescope is reporting the discovery of another moon orbiting the icy dwarf planet Pluto. The moon is estimated to be irregular in shape and 6 to 15 miles across. It is in a 58,000-mile-diameter circular orbit around Pluto that is assumed to be co-planar with the other satellites in the system.

Twin Satellites Will Help Improve Space Weather ForecastsOn Aug 24, NASA will launch two identical satellites from Cape Canaveral, Florida, to begin its Radiation Belt Storm Probes (RBSP) mission to study the extremes of space weather and help scientists improve space weather forecasts.

Early Black Holes Grew Big Eating Cold, Fast FoodResearchers at Carnegie Mellon University's Bruce and Astrid McWilliams Center for Cosmology have discovered what caused the rapid growth of early supermassive black holes -- a steady diet of cold, fast food.

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A pictorial impression of space weather phenomena has been shown in the figure below. The space in the solar system is not empty, instead it is filled with a magnetized mixture of ions and electrons i.e. plasma which originates from the Sun. This plasma is not stationary but flows and forms the solar wind. The solar wind carries the interplanetary magnetic field (IMF) and flows throughout the heliosphere at an average speed of about 250-400 km per second when the Sun is quiet. The solar wind reduces its speed as it encounters the bow shock around the magnetosphere of the Earth some 90,000 km away. The thickness of the bow shock has been found to be 17.3 km. This is the first barrier blocking the emissions from the Sun.After breaking the bow shock, the solar wind enters the magnetosphere of the Earth and may change both geometry and magnitude of the magnetic field around Earth. The variation in the geomagnetic field (i.e. the magnetic field of Earth) can be observed using space and/or ground based systems and observatories. The solar wind brings charged particles with it and these ions get trapped by the geomagnetic lines of force. They gather at north and/or south poles to produce magnificent light curtains known as aurora. The auroral zone is roughly a span of 10° to 20° with respect to the geomagnetic poles of the Earth.

Aurora is one of the most spectacular visible impressions of space weather which can be observed with the naked eye. The colours of an aurora depend upon the chemical composition of air emitting the light energy when air molecules interact with the charged particles from the Sun.

The excessive radiations, charged particles and magnetic field from the Sun affect technological systems both in space and on ground. One of the most severe space weather events was recorded in September 1859 as Carrington’s Event (after the name of a British astronomer Richard Carrington). He observed mega solar flares using his telescope and recorded them to produce a research paper. It is said that modern technological systems are highly vulnerable to one such event if it happens today. Although the probability of such event is 1-in-100-year but, the damage would be in trillions of dollars with a recovery period of several years.

More details about the types of space weather events would be given in the next issue of this bulletin.

Understanding Space Weather (Cont)

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No major geomagnetic activity was reported in the month of Sep 2012. However the plots given in the figure show the geomagnetic field variation on magnetically quiet days. The magnetograms of figure have been plotted for 4 days starting from 22-Sep-2012.

SUPARCO shares geomagnetic data with World Data Centre (WDC) and provides services to national users. The data is acquired in HDZ format where H and Z are the horizontal and vertical components of the geomagnetic field and D is the declination (i.e. the angle between magnetic north and true north). The magnetogram acquired have been shown in the plot which exhibits variations in the local geomagnetic field at Sonmiani, Pakistan. The magnetogram contains four subplots such that the top panel shows variation in H (nT, nano tesla), 2nd panel shows variations in D (in degrees), 3rd panel contains variations in Z (nT) and last panel contains total magnetic field F (nT) variations. The universal time (UT) has been shown on the horizontal axis.

The vector diagram shows the geomagnetic field vector components along with their

Geomagnetic Feild monitoring by SUPARCO

Image source http://wdc.kugi.kyoto-u.ac.jp/element/elefig.gif

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SPAS DirectorateGulzar-e-Hijri SUPARCO RoadSector 28, SUPARCO, Karachi, PakistanTel: 021-34690765-74Fax 021-34690795Email: sckhi@suparco.gov.pkCon

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Observation of Binary StarsTwo stars that are close together and rotate about their common center of mass (Barycenter) are called binary stars. Usually one star is brighter than the other this is called the primary and the other is called its companion.

The angle at the primary star between directions of the North Pole and the companion is called the positive angle and the angular separation between the stars is called separation denoted by “d”. There are several kinds of binary stars: Optical Binary: They appear to be close because they happen to be in this same line of light. The y are actually sever light years of past. Visual Binary: When viewed through telescope they appear as distinct stars. Their period varies from 1-year to about 1000-years. Famous visual binaries are Mizeur, Rigel, CasterSpectroscopic Binary: They are so close together that even a telescope cannot see them separately. They are detected spectroscopically through alternate red and blue shift as one star moves towards us and the other away from us. Their periods are a few days. They are so close together that some of them touch at the surface. The famous spectroscopic binary is Algol Spectrometric Binary: If the plane of the orbit is � the line of sight the radial velocity is zero and there is no red or blue shift. They are detected through contradictory spectral properties.

Algol is variable star. Its period is 29 days. People in old days believed that it was under the influence of the devil and hence it was called the “Demon Star”. It changes in brightness can be observed with naked eye. Now it is known to be an Eclipsing Binary when stars are visible the light is bright when dimmer comes in front of brighter light is very much diminished. When the brighter star comes in front of the dimmer one, the light is slightly diminished.

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An artist conception of binary stars (upper left); Bianry stars picture taken by SUPARCO, Alberio A and B (Upper right);