ESSAY Q #3 Flashcards
What observations confirm the existence of protostars?
Protostars form deep inside clouds of dust and gas that absorb any light the star may emit. Surface temp is low in the infrared spectrum.
we can find protostars based on infrared radiation, because they’re covered by clouds of gas, and that the surface temp. is low so the black body radiation is in the infrared spectrum.
Why can’t lower-main-sequence stars become giant stars?
It cannot reach nuclear fusion in the cores. It would need to be all hydrogen in the cores in order to become a giant. It would take a long time for that to happen.
Lower main sequence stars can’t become giant stars because they’re red dwarfs. That makes them small in mass and, in order to be big giant stars, they’d have to use up all the hydrogen, and that takes a lot of time.
Why do we not expect the find a 2-solar-mass white dwarf?
CHANDRASEKHAR LIMIT:
implies that a star more massive than 1.4 solar masses can not become a white dwarf unless it sheds mass in some way. It can’t fight the mass so it collapses.
What observational evidence do we have that black holes exist?
Through X-ray emission. We see it indirectly through X-ray radiation and see that some kind of material falls into hole and heats up causing the X-ray emission.
What is the difference between a Population 1 star and a Population 2 star?
POP 1:Metal rich (2-3% metals), Young (blue), Next generation. Sun is pop 1. FOUND- in a disk
POP2:Metal Poor (1%), Old (red). FOUND- in a halo.
