ASTR 121 Study Guide - Midterm Guide: White Dwarf, Quasar, Accretion Disk

• School: University of Maryland
• Department: Astronomy
• Course: ASTR 121
• Professor: Derek Richardson

Document Summary

The milky way appears in our sky as a faint band of light due to dusty gas clouds that absorb visible light. This is the interstellar medium that makes new star systems. We see the milky way galaxy edge-on from the inside, and it has three distinct features: the disk, bulge, and halo. Its spiral arms are visible if we could see above the disk. Each star moves purely under the action of gravity due to the milky way"s gravitational field. Has lots of dust and gas (rotates in an orderly way in the same direction, but bobs up and down due to its gravity) Consists of stars of all ages including young ones (population 1) Very thin (30 kpc in diameter, 300-600 pc thick) Thick oblate spheroid (few kpc in diameter) Contains mostly old stars and has the majority of stars in the galaxy (population 2)