• Home
  • Textbooks
  • Universe: Solar System, Stars, and Galaxies
  • Neutron stars and Black Holee

Universe: Solar System, Stars, and Galaxies

Michael Seeds, Dana Backman

Chapter 16

Neutron stars and Black Holee - all with Video Answers

Educators

Chapter Questions

01:09

Problem 1

If a neutron star has a radius of $10 \mathrm{km}$ and rotates 716 times a second. what is the speed of the surface at the neutron star's equator as a fraction of the speed of light?

Prabhu Ramji
Prabhu Ramji
Numerade Educator
View

Problem 2

Suppose that a neutron star has a radius of $10 \mathrm{km}$ and a temperature of 1,000,000 K. How luminous is it? (Hint: Use the luminositytemperature-radius relation, Chapter $13 .$

Lainey Roebuck
Lainey Roebuck
Numerade Educator
04:57

Problem 3

A neutron star and a white dwarf have been found orbiting each other with a period of 11 minutes. If their masses are typical, what is their average separation? Compare the separation with the radius of the sun, $7 \times 10^{5} \mathrm{km} .$ (Hints: Use the version of Kepler's third law for binary stars, Chapter $13 ;$ make sure you express quantities in units of $\mathrm{AU}$, solar masses, and years.)

Matthew Miranda
Matthew Miranda
Numerade Educator
01:17

Problem 4

If the accretion disk around a neutron star has a radius of $2 \times 10^{5} \mathrm{km}$ what is the orbital velocity of a particle at its outer edge? (Hint: Use the formula for circular orbit velocity, Chapter $4 .$

Prabhu Ramji
Prabhu Ramji
Numerade Educator
01:26

Problem 5

What is the escape velocity at the surface of a typical neutron star? (Hints: The formula for circular orbit velocity is in Chapter 4; escape velocity equals circular orbital velocity times the square root of 2 which is about $1.41 .$

Farhanul Hasan
Farhanul Hasan
Numerade Educator
04:44

Problem 6

If Earth's moon were replaced by a typical neutron star, what would the angular diameter of the neutron star be as seen from Earth? (Hint: Use the small-angle formula, Chapter $3 . .$

Vedad Babic
Vedad Babic
Numerade Educator
01:12

Problem 7

If the inner accretion disk around a black hole has a temperature of $1,000,000 \mathrm{K},$ at what wavelength will it radiate the most energy? What part of the spectrum is this in? (Hint: Use Wien's law, Chapter $6 .$

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
02:06

Problem 8

What is the orbital period of a bit of matter in an accretion disk $2 \times 10^{5} \mathrm{km}$ from a 10 -solar-mass black hole? (Hint: Use the circular orbit velocity formula, Chapter $4 .$

Narayan Hari
Narayan Hari
Numerade Educator
02:47

Problem 9

If an X-ray binary consists of a 20-solar-mass star and a neutron star orbiting each other every 13.1 days, what is their average separation? (Hints: Use the version of Kepler's third law for binary stars, Chapter 13 ; make sure you express quantities in units of AU, solar masses, and years.)

Joseph Petrullo
Joseph Petrullo
Numerade Educator