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Tyler Junior College Department of Physics and Astronomy Presents. Lab 5-6 Star Stuff. Star Color. The Color of star is determine by the star’s: Age Nuclear Fuel Radius The Gravity / Fusion Pressure. Classification of Stars. * *. * M O = M sun & R O = R Sun.
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Tyler Junior College Department of Physics and Astronomy Presents Lab 5-6 Star Stuff
Star Color • The Color of star is determine by the star’s: • Age • Nuclear Fuel • Radius • The Gravity / Fusion Pressure.
Classification of Stars * * * MO = Msun & RO = RSun · · · Examples: CLASS STAR CONSTELLATION O- Alnitak (ζ Orion) Orion B- Rigel (β Orion) Orion A- Sirius (α Canis Maj) Canis Major F- Polaris (α Ursa Min) Ursa Minor G*- Capella (α Auriga) Auriga K- Arcturus (α Bootes) Bootes M- Betelgeuse (α Orion) Orion * Sol (Our Sun)
Star Class Comparisons • Temperature (°K) M (3,700°K) < K< G < F < A < B < O (30,000°K) Coolest Hottest • Mass (Msun) M (0.45MSun) < K < G < F < A < B < O (16MSun) • Radius (RSun) M (0.7 RSun) < K < G < F < A < B < O (6.6RSun) Smaller Larger • Luminosity(LSun) M (<0.08 LSun) < K < G < F < A < B < O(>30,000 Lsun) Fainter Brighter
Spectra Class Expanded • Each class is expanded by adding a number after the Spectra Class (letter) to indicate the stars ranking in the Class • A5 means that the star is A class and 0.5 between A0 and F0. • Sirius is an A1 star. Our Sun (Sol) is a G2. • Dwarf Star have their own classification system.
Fuel Composition H He
Additional Stellar Classes STELLAR LUMINOSITY CLASSES • I Super giants • II Bright giants • III Giants • IV Sub giants • V Main-sequence stars • wd white dwarfs
Stars and their luminosity Classes • Spica B1 V • Sirius A1 V • Betelgeuse M2 I • Rigel B8 I • Pollux K0 III • Procyon F5 IV-V • Sun (Sol) G2 V • ProximaCenturi M5.5 V • Sirius B DA2* wd * White Dwarf
Luminosity, Size, Magnitude, DistanceTemperature STAR DISTANCE SPECTRAL MAGNITUDE LUMINOSITY • Sun 0.000016 ly G2 V -26.74 1.0 LSUN • Sirius 8.6 ly A1 V -1.46 26 LSUN • Betelgeuse 427 ly M2 I 0.41 38,000 LSUN • Rigel 772 ly B8 I 0.14 70,000 LSUN • Pollux 34 ly K0 III 1.16 45 LSUN • Procyon 11.4 ly F5 IV-V 0.37 7.4 LSUN • α Centauri A 4.4 ly G2 V -0.01 1.6 LSUN • α Centauri B 4.4 ly K0 V 1.3 0.53 LSUN • Sirius B 8.6 ly DA2 8.3 0.26 LSUN
Lab 5 Stellar Spectra with a Virtual Telescope
The End Lab 5 Stellar Stuff