Stars
Astronomers measure distances in the universe in _______________
Light years
Stars are composed of _________ and ___________
hydrogen and helium
A hot but dim dying star
white dwarf
The sun is a _____________________________ star
main sequence
About 90% of the stars, including the sun, are _______________________________ because they fuse hydrogen into helium as their fuel source
main sequence
The sun's closest star neighbor is ___________________
Proxima Centauri
A relatively old star whose temperature has cooled and its diameter is about 100 times bigger than it was originally is a ______________________________
Red giant
nuclear fusion
when a star fuses hydrogen into helium
Most galaxies have a __________________________ at the center.
Super massive black hole
protostar
Red supergiants are _________ and luminous.
cool
number of regions the sky is divided into
88
When most massive stars die, they become ________________________________
Black holes
apparent surface of the sun
photosphere
What does the Sun and our solar system orbit?
center of Milky Way
life cycle of a low/average mass star
How bright a star appears to be due to how close or far away it is ____________________________
apparent magnitude
Cast off of hydrogen and helium from white dwarf that is recycled to make new stars
planetary nebula
6 layers of the Sun and stars beginning in the center
A type of compact star that can result from the gravitational collapse of a massive star after a supernova
neutron star