Stars 2

Question 1

Pauli’s exclusion principle

Answer 1

No two electrons can occupy the same quantum state

Question 2

Electron Degeneracy Pressure (4)

Answer 2

• Electrons exert a degeneracy pressure when confined to a finite sized region.
• This pressure supports white dwarfs
• Does not depend on temperature, can balance gravity indefinitely
• Scales with radius faster than gravitational pressure, so stable radius will be met

Question 3

Electron Degeneracy Energy Equation

Answer 3

E = (h^2 n ^2/3 ) / 2m

h is plankcs constant, n is electron number density, m is electron mass

Question 4

Chandrasekhar Limit (4)

Answer 4

• At higher masses, relativistic momentum means gravitational and degeneracy pressure scale at same rate
• If mass is too large, the star will collapse
• For white dwarfs : 1.44M⊙
• For neutron stars: 2-3M⊙

Question 5

Escape Velocity

Answer 5

• The velocity required for an object to escape the gravitational potential of a mass
• Found when kinetic energy equates to gravitational potential energy

Question 6

Escape Velocity Equation

Answer 6

V^2 = 2GM/R

Question 7

Schwarzschild Radius

Answer 7

• The radius an object must have to become a black hole
• Found when escape velocity is set to speed of light as nothing can escape a black hole