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21 Cards in this Set

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Open Cluster

A few thousand loosely packed stars

Globular Cluster

Up to a million or more starts in a dense ball bound together by gravity

Interstellar Medium

the gas between stars

Flattening

collisions between particles in the cloud cause it to flatten into a disk

Fusion will not begin in a contracting cloud if some sort of force stops contractions before the core temperature rises above ____

10^7 K

_________ cannot stop contraction because the star is constantly losing it through radiation

Thermal pressure

Main form of pressure in most stars

thermal, depends on heat content

Degeneracy pressure

particles cant be in same state in same place, does not depend on heat content

Brown Dwarfs

degeneracy pressure halts contraction before core temperature becomes hot enough for fusion, they are not massive enough to start fusion, emit infrared light because of heat left over from contraction, luminosity gradually declines with time as it loses thermal energy

____ pressure limits how massive a star can be without blowing itself apart

Radiation

Maximum radiation pressure thought to be

150M Sun

Life stages of low mass star

11.5 million years. Protostar, yellow main sequence star, reg giant star, helium burning star, double shell burning red giant, planetary nebula, white dwarf



Planetary Nebulae

Double shell burning ends with pulse that eject the H and He into space, the core left behind becomes a white dwarf

Stages of high-mass star

5 million years, protostar, blue main sequence, red supergiant, helium burning supergiant, multiple shell burning supergiant, supernova, neutron star of black hole

Supernova Explosion

Core degeneracy pressure goes away because electrons combine with protons, making neutrons and neutrinos, neutrons collapse to the center, forming a neutron star

_________ says that electrons must move faster as they are squeezed into a very small space

quantum mechanics

White dwarf cannot be more massive than

1.4M sun (white dwarf limit)

Accretion Disks

Mass falling toward white dwarf from its close binary companion and has some angular momentum, the matter therefore orbits the white dwarf. friction between orbiting rings of matter in the disk transfers angular momentum outward and causes the disk to heat up and glow

Nova

The temp of the accreted matter eventually becomes hot enough for hydrogen fusion, fusion begins suddenly and explosively causing a nova

Massive star supernova

iron core of massive star reaches white dwarf limit and collapses into a neutron star, causing total explosion


White dwarf supernova

Carbon fusion suddenly begins as a white dwarf in close binary system reaches white dwarf limit, causing total explosion