| A | B |
|---|
| stars | made up mostly of large amounts of hydrogen gas in a small volume |
| sun | the closest star to Earth, average in brightness, medium in size, part of the Milky Way |
| 3 characteristics used to classify stars | size, temperarture, brightness |
| supergiant stars | very large stars ex. Betelgeuse |
| giant stars | large stars |
| medium size stars | most stars such as the sun |
| white dwarf stars | small stars size of Earth |
| neutron stars | very small stars-20 kilometers |
| red | the collest star, 3,500 degrees Celsius |
| white | about 6,000 degrees Celsius |
| blue | the hottest stars, more than 10,000 degrees Celsius |
| brightness depends on | size and temperature |
| apparent magnitude | how bright a star appears from Earth. Stars that are colse to Earth appear brightre |
| absolute magnitude | the actual brightness of a star |
| small stars | use their fuel slowly, and live longer up to 200 billion years |
| medium stars live | up to 10 billion years |
| very massive stars live | for about 10 million years |
| nebulae | is a large amount of gas and dust spread out in a large volume |
| protostar | gas and dust in the nebulae begin to contract because gravity pulls it together |
| newborn star/ main sequence | the contracting gas and dust become haot and nuclear fusion begins forming a newborn star.Nuclear fusion is when atoms of hydrogen combine and are changed into atoms of helium plus energy. The energy stops the star from contracting . The star beings to release energy. |
| white dwarf | the blue-white hot core of the star is left behind from small and medium stars.They glow from left over energy, when it stops glowing it is dead and is called a black dwarf |
| neutron star | formed from the materisl left behind after a giant or supergiant star has exploded. The explosion is called a supernova |
| black hole | the gravity of this mass is so strong that the gas is pulled inward nd nothing can escape not even light |
