Physics Of Stars

Question 1

Key star ranges
Temp
Luminosity
Mass
Radius

Answer 1

3000-200000K
10^-4 - 10^6 Lsun
0.08 - 120 Msun
0.01 - 500 Rsun

Question 2

Hertzprung Russell diagram

Answer 2

Colour vs absolute magnitude

Question 3

Stella classification

Answer 3

OBAFGKM(LT)
Sub classes 0-9
O3 - M9 (hottest to coldest stars)
Sun = G2
LT = brown dwarfs

Question 4

Timescales

Answer 4

Dynamic (R/Vesc)
Kevin-Helmholtz (Ep/Luminosity)
Shine (fM/L)

Question 5

Energy generation in stars

Answer 5

Nuclear fusion of; 4 Hydrogen to produce a He 4 nucleus (PP Cycle), He to produce B, or CNO cycle if conditions allow

Continues until H used up and inner regions contract

Question 6

End state of a low mass star (5 solar masses)

Answer 6

White dwarf
Burns up to carbon and then is stabilises by the electron degeneracy pressure
Electron degeneracy pressure - electrons in lowest energy levels (2 per level)

Question 7

End state of a high mass star

Answer 7

Neutron star (1.8-2.9 solar masses)
Black hole 

Burns up to silicon
Energy removed by - neutrinos, electron capture, photondisintergration
Core collapses to neutron star or black hole and outer layers blown off (SUPERNOVA)
Neutron star is stabilised by neutron degeneracy pressure