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30 terms

Stars & Galaxies

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absolute magnitude
the actual (true) brightness of a star
apparent magnitude
the brightness of a star as seen from Earth
barred spiral galaxy
a galaxy that is similar to a spiral galaxy, except that the spiral arm pattern originates from a bar of material that passes through the nucleus of the galaxy.
binary star
a system of two stars that revolve around each other under their mutual gravitation
black hole
final stage in the evolution of a very massive star, where the core's mass collapses to a point that its gravity is so strong that not even light can escape
circumpolar
stars that appear to travel in a circle around the celestial poles
constellation
A group of stars that form a pattern in the sky
elliptical galaxy
a galaxy shaped like a round or flattened ball, generally containing only old stars
galaxy
a collection of stars, dust, and gas bound together by gravity
giant star
a very large, cool, bright star; much larger than the sun
globular cluster
spherically shaped group of hundreds of stars located around the core of the Milky Way Galaxy
H-R Diagram
Hertzsprung-Russell diagram, a graph that shows the relationship between a star's surface temperature and absolute magnitude
irregular galaxy
a galaxy that does not fit into any other category; one with an irregular shape
light year
the distance light travels in one year (9.5 trillion kilometers)
main-sequence star
a normal star that is undergoing nuclear fusion of hydrogen into helium. Our sun is a typical main sequence star.
nebula
a large cloud of dust and gas that can break apart into smaller pieces and form stars, large cloud of gas and dust that contracts under gravitational force and breaks apart into smaller pieces, each of which might collapse to form a star
neutron star
collapsed core of a supernova consisting of a small, extremely dense ball of neutrons
nova
white dwarf star that explodes as it cools, temporarily becoming thousands of times brighter
open cluster
a star cluster that has a loose, disorganized appearance and contains no more than a few thousand stars
parallax
method of determining the distance from the earth to a star based on the shift in the apparent position of the star when viewed from different angles
planetary nebula
expanding shell of gases shed by a dying star
protostar
Early form of a star; This stage lies between the collapsing of dust and gas and the beginning of nuclear fusion
pulsar
neutron star that emits two beams of radiation that sweep across space
quasar
a starlike object that may send out radio waves and other forms of energy
red shift
the change in the wavelength of light due to an object moving away from the observer.
spiral galaxy
a galaxy with a bulge in the middle and arms that spiral outward in a pinwheel pattern
star
a body of gases that gives off a tremendous amount of radiant energy in the form of light and heat
supergiant
an extremely large, giant star
supernova
the brilliant explosion of a dying supergiant star
white dwarf
a small, hot, dim star that is the leftover center of an old star