Astronomy

1. Astronomy

2. What is Astronomy? The scientific study of matter in outer space, especially the positions, dimensions, distribution, motion, composition, energy, and evolution of celestial bodies and phenomena. The study of anything in space.

3. Some Items in Space • Stars • Dwarfs • Red, White, Black, Brown, L, T • Neutron • Black Holes • Super Giants • Constellations • Astrology • Solar Systems • Planets

4. Stars in General A celestial object composed of gas held together by its own gravity and supported by nuclear fusion occurring in its interior. A self-luminous celestial body consisting of a mass of gas held together by its own gravity in which the energy generated by nuclear reactions in the interior is balanced by the outflow of energy to the surface, and the inward-directed gravitational forces are balanced by the outward-directed gas and radiation pressures. Any of the celestial bodies visible at night from Earth as relatively stationary, usually twinkling points of light. Something regarded as resembling such a celestial body. Something pretty in the sky

5. Specific Types of Stars 1 • Binary Stars • They are pairs of stars moving in orbit around their common centre of mass. They are also known as double stars. An optical pair appears to be double because two stars lie in the viewer's line of vision. Examples of double stars are Phakt in Columba and Arcus in Crux. • Black Dwarf • It is the remains of a dead white dwarf star after its heat is radiated into space. • Black Hole • It is what remains of a super collapsed star, whose gravitational pull is so great that no light can escape. • Brown Dwarf • It is a star whose mass is too small to have fusion occur at its core because the temperature and pressure there are too insufficient. It is also not very luminous. • Galaxy • It is a system of stars, dust, and gas held together by gravity. There are three basic types: spiral, elliptical, and irregular. • A spiral galaxy is a flattened, discus-shaped collection of stars, having a central bulge. Examples include the Milky Way and Andromeda. • An elliptical galaxy ranges in shape from a sphere to a flattened globe. Examples include the Sagittarius Dwarf and M31. • An irregular galaxy has no pattern of shape. Examples include the Large Magellanic Cloud and the Small Magellanic Cloud. • Main-Sequence Stars • It is an ordinary star, one of about 90% of the stars that can be seen from Earth. It is much smaller than a giant star. It burns hydrogen into helium through nuclear fusion within itself. An example is our Sun.

6. Specific Types of Stars 2 • Nebula • It is a cloud of gas or dust, and is considered to be the birthplace of a new star. There are three basic types: emission, reflection, and dark. • An emission nebula glows brightly because its gas is energized by the stars formed within it. An example is the Orion Nebula. • A reflection nebula is one in which sunlight reflects off the grains of dust within it. An example is the one which surrounds stars of the Pleides cluster. • A dark nebula is a dense cloud of molecular hydrogen which absorbs light behind it. Examples are the Horsehead Nebula in Sagittarius and the Crab Nebula in Taurus. • Neutron Star • It is the tiniest star, having collapsed into a superdense state. It is thought to have formed when a large star exploded as a supernova. • Nova • It is a star that brightens suddenly, lasts a few days, fades away, and returns to its normal state. • Pulsar • It is a rapidly spinning neutron star that emits pulses of energy. • Quasar • It is a quasistellar object, very far away and very bright. It gives off more energy than one hundred giant galaxies. • Red Giant • It is a large, bright star, many times larger than the Sun, but with a cool surface. It is believed to be in the end stage of its life cycle. Examples are Aldebaran in Taurus and Ras Algethi in Hercules.

7. Specific Types of Stars 3 • Star Colours • They are, in descending order of temperature, greenish, blue, blue-white, yellowish-white, yellow, orange-yellow, orange-red, red, infrared. • Supergiant • It is the largest and most luminous type of star, being a dying star. It has used up its hydrogen fuel and has begun to expand and cool. Examples are Antares in Scorpius and Betelgeuse in Orion. • Supernova • It is an exploding supergiant, being the death of a star. The Crab Nebula was formed by a supernova. • Variable Star • It is a star whose brightness changes. This is usually caused by pulsations within it. Examples of variable stars are Polaris in Ursa Minor (Cepheid) and R Centauri in Centaurus (Mira). • White Dwarf • It is a very dense, small, hot star in the last stage of its life. It occurs when a red giant sheds its outer layers as a planetary nebula. The electrons and protons have been packed as closely as possible by gravity. An example of the white dwarf is the Pup, companion star of Sirius in Canis major. • Wolf-Rayet Star • It is a hot, luminous star that is rapidly losing mass in a wind. It represents a late stage in the life of massive stars.

8. Dwarf Stars • A star, such as the sun, having relatively low mass, small size, and average or below average luminosity. • They following are a list of different type of dwarfs stars and an example of each. • Red Dwarfs Ex-Barnard's star • White Dwarfs Ex-Sirius B • Black Dwarfs Ex-none in our universe • Brown Dwarfs Ex-Gliese 229 B • L Dwarfs Ex-A cooler Brown Dwarf • T Dwarfs Ex-A cooler Brown Dwarf • Yellow Dwarf Ex-Our Sun

9. Neutron • It is the tiniest star, having collapsed into a superdense state. It is thought to have formed when a large star exploded as a supernova. A star that has collapsed under its own gravity; it is composed of neutrons A small, highly dense star composed almost entirely of tightly packed neutrons; radius about 10 km.

10. Black Hole • It is what remains of a super collapsed star, whose gravitational pull is so great that no light can escape. An area of space-time with a gravitational field so intense that its escape velocity is equal to or exceeds the speed of light. A mass that has collapsed to such a small volume that its gravity prevents the escape of all radiation; also, the volume of space from which radiation may not escape.

11. SuperGiants • It is the largest and most luminous type of star, being a dying star. It has used up its hydrogen fuel and has begun to expand and cool. Examples are Antares in Scorpius and Betelgeuse in Orion. • Any of various very large bright stars, such as Betelgeuse or Rigel, having • a luminosity that is thousands of times greater than that of the sun. Exceptionally luminous star 10 to 1000 times the sun’s diameter.

12. Constellations An arbitrary formation of stars perceived as a figure or design, especially one of 88 recognized groups named after characters from classical mythology and various common animals and objects. One of the stellar patterns identified by name, usually of mythological gods, people, animals, or objects; also, the region of the sky containing that star pattern. An area of the celestial sphere occupied by one of the 88 recognized constellations. A picture in the sky made up of stars.

13. Names of the Constellations Andromeda Corvus Monoceros Tucana Antilia Crater Musca Ursa Major Apus Crux Norma Ursa Minor Aquarius Cygnus Octans Vela Aquila Delphinus Ophiuchus Virgo Ara Dorado Orion Volans Aries Draco Pavo Vulpecula Auriga Equuleus Pegasus Bootes Eridanus Perseus Caelum Fornax Phoenix Camelopardalis Gemini Pictor Cancer Grus Pisces Canes Venatici Hercules Piscis Austrinus Canis Major Horologium Puppis Canis Minor Hydra Pyxis Capricornus Hydrus Reticulum Carina Indus Sagitta Cassiopeia Lacerta Sagittarius Centaurus Leo Scorpius Cepheus Leo Minor Sculptor Cetus Lepus Scutum Chamaeleon Libra Serpens Caput/Cauda Circinus Lupus Sextants Columba Lynx Taurus Coma Berenices Lyra Telescopium Corona Australis Mensa Triangulum Corona Borealis Microscopiums Triangulum Australe

19. Zodiac A belt-shaped region in the heavens on either side to the ecliptic; divided into 12 constellations or signs for astrological purposes A circular diagram representing the 12 zodiacal constellations and showing their signs A band of the celestial sphere extending about 8° to either side of the ecliptic that represents the path of the principal planets, the moon, and the sun. In astrology, this band divided into 12 equal parts called signs, each 30° wide, bearing the name of a constellation for which it was originally named but with which it no longer coincides owing to the precession of the equinoxes. A diagram or figure representing the zodiac.

20. The Zodiacs Name Symbolizes Birthdays • AriesThe RamMarch 21-April 19 • TaurusThe BullApril 20-May 20 • GeminiThe TwinsMay 21-June 20 • CancerThe CrabJune 21-July 22 • Leo The LionJuly 23-August 22 • VirgoThe VirginAugust 23-September 22 • LibraThe Balance September 23-October 22 • ScorpioThe Scorpion October 23-November 21 • SagittariusThe ArcherNovember 22-December 21 • Capricorn The GoatDecember 22-January 19 • AquariusThe Water Bearer January 20-February 18 • PiscesThe FishesFebruary 19-March 20

21. Our Solar System • Sun • Mercury • Venus • Earth • Mars • Jupiter • Saturn • Neptune • Uranus • Pluto

22. Sun

23. Mercury

24. Venus

25. Earth

26. Mars

27. Jupiter

28. Saturn

29. Uranus

30. Neptune

31. Pluto

32. References • http://dictionary.reference.com/ • http://members.aol.com/bobalien99/stardiff.htm • Seeds, Michael. Foundations of Astronomy. 8th. Canada: Thomas Learning, Inc, 2005. • http://vegas.astronomynv.org/Tutorials/Twinkle.htm • http://en.wikipedia.org/wiki/Brown_dwarf • http://www.answers.com/black%20dwarf%20 • http://uanews.org/cgi-bin/WebObjects/UANews.woa/8/wa/SRStoryDetails?ArticleID=12395 • http://www.innvista.com/science/astronomy/types.htm • http://www.skynightly.com/images/brown-dwarf-pair-bg.jpg • http://loonix.technigga.net/stars.jpg • Sasaki, Chris. The Constellations Stars & Stories. New York: Sterling Publishing Co., Inc, 2003. • http://www.people.memphis.edu/~jschmelz/images/03_Constellation_Orion.jpg • http://library.thinkquest.org/12523/media/Star_SG.jpg • http://images.usatoday.com/tech/_photos/2006/05/02/neutron.jpg • http://www.ccsd.k12.wy.us/Scie.../images/solar_system_small.gif

33. References Continued • http://www.panoptikum.net/sonnensystem/sun.jpg • http://www.dl.ket.org/latin1/things/planets/images/mercury.jpg • http://www.drfreund.net/bigfiles/images/titlepics_solarsystem/venus_total.jpg • http://www.d21c.com/AAALynx/CB/pl/earth.jpg • http://lexikon.astronomie.ch/mars/img/im-mars.jpg • http://cecelia.physics.indiana.edu/life/nineplanets/jupiter3.gif • http://archives.cnn.com/2000/TECH/space/10/25/Saturn.moons/saturn.jpg • http://www.b22.de/gallery/BRehse/Web/Uranus.jpg • http://www.ssec.wisc.edu/media/spotlight/images/neptune.jpg • http://www.b22.de/gallery/BRehse/Web/Pluto.jpg • http://www.capricorn007.com/zodiac2.html • Lehner, Ernst and Johanna. Astrology and Astronomy: A Pictorial Archive of Signs and Symbols. Mineola, New York: Dover Publications, Inc, 2005.