Interstellar medium

Question 1

interstellar reddening

Answer 1

dust affects shorter wavelengths

Question 2

reflection nebula

Answer 2

light reflected onto dust cloud in our line of sight

Question 3

extinction

Answer 3

absorption and scattering of light due to dust obscuring light from celestial objects

Question 4

spectroscopic parallax

Answer 4

determine spectral type from luminosity

Question 5

Polarization

Answer 5

dust polarizes light (appear in single plane)

Question 6

albedo

Answer 6

fraction of light scattered

Question 7

H I clouds

Answer 7

mostly neutralized hydrogen (molecules dont form)

Question 8

H II regions

Answer 8

ionized hydrogen

Question 9

molecular clouds

Answer 9

H in molecular form

Question 10

heating dust

Answer 10

dust absorbs photon and heats up

Question 11

excitation of molecules/atoms

Answer 11

photon strikes mol/atom directly

Question 12

ionization

Answer 12

photon ionizes mol/atom

Question 13

photoelectric effort

Answer 13

photon strikes dust grain, ejects electron

Question 14

grain emission

Answer 14

grain heats from collisions and radiates

Question 15

excitation

Answer 15

emits photon