White Dwarf

Neutron Star

Black Hole

• Low-mass stars end their lives this way
• The sun will end it's life this way
• the low mass star will move through its planetary nebula stage, with the central core of the star remaining as the ________

• There is a limit to it's size
• the carbon core of a low mass star cannot be more than 1.4Msun
• if the mass is below this limit any material added to its surface (through accretion of a companion) will be blown off in a Nova
• If the _____ continues to accret matter and acheives 1.4msun, it will eject that matter in a ____ super nova. A ____ supernova has a different effect than a massive star supernova, so we can tell the difference
• pretty dense objects, about the mass of the sun squeezed into the size of earth!

• A high mass star (M >8Msun), can end its life in one of two ways: ____ or a black hole
• as the core of the massive star collaspes (during a supernova) the iron ions get compressed together. Iron will cease to exist. All the electrons in the plasma join together with protons to become nuetrons (due to high density here)
• So now all we have left is a ball of nuetrons- or a _______. It is not really a star anymore. The object is not generating its own heat it is just radiating the heat left over from the death of the star

• more dense than a white dwarf
• about the size of a sity with a mass greater than our sun but cannot exceed 2-3 sollar masses
• Was discovered by accident, was postulated to exist

• Can spin as slowly as a few times per second or as quickly as hundreds or times per second
• All pulsars are _____ but not all ______ are pulsars. They are really only pulsars if that beam of energy sweeps by the earth

• If the mass of the left over core of the massive star is greater than 3 solar masses (this would probably be a star that started out at 20 solar masses), the star goes through a supernova and the core collaspse
• Then the "nuetron star" core gains too much mass and now has enough mass to contract even further!
• Now nuetrons will be crushed into a singularity - this is essentially a _________
• A place where the curvature of space-time is so extreme that nothing can escape its gravity

1. The singularity: A 1 dimensional point in space-time: has infinite density
2. The event Horizon: A spehere around the singularity; the size of the event horizon depends on the mass of the black hole; the escape velocity at this boundry is the speed of light; nothing can escape, outside this boundary you are "safe"