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Galaxies
Galaxies come in different shapes and sizes. The largest are spiral galaxies which have a flattened disk with spiral arms and a bulge in the center. Elliptical galaxies have no definite shape and little gas or dust. Irregular galaxies have an irregular shape and active star formation. Well-known galaxies include the Andromeda Galaxy, Whirlpool Galaxy, Sombrero Galaxy, and Sunflower Galaxy.
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Galaxies
- 5. GALAXY System of millionsof billions of stars Large group of stars, gas, dust that constitute universe Most of Galaxy have blackhole at the center GALAXY
- 9. Globular Clusters Colletion ofmillions of ancient star More densed and spherical shape Lack of O and B type of star 150 known in Milkyway galaxy
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- 11. Cepheid Variables • verylarge, luminous, yellow stars • called Cepheids after the first star of this type to be discovered - Delta Cephei • Special variable stars : (a) regular (b) a uniform function of their brightness
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- 13. Milky way Galaxy •Named after the niboulosity of night sky • William Hershel (1985) • 100,000 light years and 1000 light years thick. • Rotation - 250 km/h
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- 15. The structure ofthe Milky Way • Bulge • Disk • Halo • Nucleus • Dark Matter
- 18. ELLIPTICAL GALAXY Smooth andelliptical in appearance Characteristics: (a). They must have random star motion rather than rotational motion. (b) They have very little gas and dust left between the stars. ELLIPTICAL GALAXY
- 19. ELLIPTICAL GALAXY They haveno star formation occuring and no hot, bright massive star in there. No spiralstructure. ELLIPTICAL GALAXY
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- 21. SPIRAL GALAXY • Flatteneddisc with spiral disc The spiral arms can go all the way to bulge or be attached to the ends of a long bar of gas and dust.
- 22. Characteristics: (a) They havemore orderly, rotational motion than random motion. (b)They have some or lot of gas and dust between the stars (c) They can have new star formation particularly in spiral arm (d)Spiral structure SPIRAL GALAXY
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- 24. IRREGULAR GALAXY No definiteshape It has a lot of gas and dust so star formation is possible Small and faint Example: the small magellanic clouds
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- 27. ANDROMEDA • also knownas M31 • crowded double nucleus • 450 globular clusters • the largest galaxy in the Local Cluster
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- 29. • NGC 4565 •thin disk structure • 240 globular clusters • 30 to 50 million light- years • constellation Coma Berenices. Needle Galaxy
- 30. • Messier 63(NGC 5055) • About the Object • Name: Messier 63 • Type:Local Universe : Galaxy : Type : Spiral • Distance:35 million light years Constellation:Canes Venatici • Category: Galaxies Sunflower Galaxy
- 31. NGC 1365 • barredspiral galaxy located in Fornax constellation • approximately 56.2 million light years distant from the Sun. • approximately 200,000 light years in diameter • ROTATION :350 million years
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- 35. • Messier 104(M104) • galaxy's hallmark is a brilliant white, bulbous core encircled by the thick dust • ilted nearly edge-on • 50,000 light-years across and is located 28 million light-years from Earth. Sombrero Galaxy
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- 37. • elliptical galaxy •located around 60 million light-years from Earth • They called it “Galactic Serial Killer” • small globular star clusters. • brightest source of radio emission in the constellation NGC 1316
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- 39. Messier 32 • mallyet bright companion of the Great Andromeda Galaxy • elliptical dwarf of only about 3 billion solar masses • Smallest Galaxy
- 40. • a tinydwarf irregular galaxy • 5,000 light years across. • 4.31 million light years distant from Earth. • located within the Local Group of galaxies. Sextans A
- 41. References • http://www.space.com/29717-globular- clusters.html • http://earthsky.org/space/milky-way-rotation •http://ircamera.as.arizona.edu/NatSci102/Nat Sci102/lectures/milkywayparts.htm