As material is added to the accretion disk, _____ may reach a temporary fusion point.

Contact binaries may allow a white dwarf star to repeat

A supernova occurs when a _____ star runs out of fuel (or overloads) and explodes.

A ____ star with a mass of 1.4 suns may go supernova (I) if too much material accretes.

Type II supernovae occur when a star with at least ____ times the mass of our sun explodes.

Supernova 1987(a) occurred in this nearby galaxy 186,000 light years away.

Supernovae regularly occur in galaxies throughout the visible Universe.

Type II supernovae explosions may leave behind a

Neutron stars are formed when gravity squeezes electrons & _____ into neutrons in a supernova.

Neutron stars are between 1.4 - 3.2 solar masses and are compacted into an area

One teaspoon of neutron star material can weigh more than

_____ are rapidly spinning neutron stars that are known as "lighthouses" in space.

Millisecond pulsars spin many times per second and have

Pulsars were first detected in the 1960's by astronomers using radio telescopes.

A black hole will form if the original star has at least _____ solar masses before collapse.

The "cutoff mass" between a neutron star and a black hole is about ____ solar masses.

The area or boundary in which nothing can return from a black hole is called

The ____ radius describes the size of the event horizon (which is black hole mass dependent).

There may be ____ of black holes in our galaxy alone - with Cygnus X-1 being the closest.