Supernovae, Neutron Stars and Black Holes

Question 1

What is a black hole? and how are they formed?

Answer 1

A black hole is an object whose escape velocity is greater than the speed of light. They are formed when a star of core mass more than 3 solar masses contracts and collapses into an infinitely dense point.

Question 2

State what is meant by a supernova?

Answer 2

An object that produces a rapid increase in brightness

Question 3

State the defining properties of a neutron star

Answer 3

-Extremely dense
-Made up of neutrons

Question 4

Neutron Star

Answer 4

Star with the density of nuclear matter, composed of neutrons

Question 5

how is a red Supergiant formed (3)

Answer 5

• When a high-mass star runs out of hydrogen nuclei, the same process for a red giant occurs, but on a larger scale. (1)
• The collapse of red supergiants in a supernova (see below) causes gamma ray bursts. (1)
• Red supergiants can fuse elements up to iron

Question 6

how is a Supernova formed (4)

Answer 6

• When all fuel runs out, fusion stops and the core collapses inwards very suddenly and becomes rigid (as the matter can no longer be forced any closer together). (1)
• The outer layers of the star fall inwards and rebound off of the core, launching them out into space in a shockwave (1)
• As the shockwave passes through surrounding material, elements heavier than iron are fused and flung out into space. (1)
• The remaining core depends on the mass of the star.

Question 7

how is a neutron star formed? (3)

Answer 7

• When the core of a large star collapses, gravity is so strong that it forces protons and electrons together to form neutrons.
• A neutron star is incredibly dense
• Pulsars are spinning neutron stars that emit beams of radiation from the magnetic poles as they spin (up to 600 times per second).

Question 8

How is a black hole formed (3)

Answer 8

• When the core of a giant star collapses, the neutrons are unable to withstand gravity forcing them together.
• The gravitational pull of a black hole is so strong that not even light can escape
• The event horizon of a black hole is the point at which the escape velocity becomes greater than the speed of light .

Question 9

When is a white dwarf formed

Answer 9

If the mass of the core is < 1.4 M solar mass then a white dwarf is formed

Question 10

When is a neutron star formed

Answer 10

If the mass of the core is > 1.4 M solar mass then a neutron star is formed

Question 11

When is a black hole formed

Answer 11

If the mass of the core is > 3.0M solar mass than a black hole is formed