Stars
Ball of hot gas held together by gravity
star
How bright a star appears to be due to how close or far away it is ____________________________
apparent magnitude
The Milky Way is a ____________________________ galaxy
spiral galaxy
Appear as dark splotches on the sun
sunspots
Nuclei of several atoms that combine into one large nucleus
Nuclear fusion
A graph plotting each star's brightness against its temperature is a _______________________________
Hertzsprung-Russell diagram
Astronomers measure large distances in a _______________
light year
This type of galaxy has no internal structure and is football shaped
elliptical galaxies
Charged particles that stream away from the sun
solar wind
A relatively old star whose temperature has cooled and its diameter is about 100 times bigger than it was originally is a ______________________________
Red giant
A group of stars bound together by gravity is a ___________
Galaxy
Most galaxies have a __________________________ at the center.
black hole
Sudden increases of brightness caused by violent eruptions on the sun
solar flares
Two stars that orbit each other
Binary star system
About 90% of the stars, including the sun, are _______________________________ because they fuse hydrogen into helium as their fuel source
Main sequence stars
The apparent change in an objects position caused by looking at it from two different angles
Parallax
These galaxies are formed from the gravitational pull of surrounding galaxies
irregular galaxies
Large explosions of plasma from the sun's corona
CME
___________________________ are what remains after a red giant star loses it outer layers; hottest stars
white dwarfs
Stars are organized on a H-R diagram according to
spectra
True brightness of an object
absolute magnitude or luminosity
This galaxy is made up of short or long arms
Spiral galaxy
Makes up about 90% of the universe
Dark energy