Question | Answer |
stars | ball of dust and gas (H and He) |
star's color | depends on temperature |
blue-colored star | 30,000 degrees |
white-colored star | 7500 degrees |
yellow-colored star | 5 to 6,000 degrees |
red-colored star | 3500 degrees (coolest) |
Stars are classified by | temperature, brightness |
Before telescopes, the brightest star in the sky was called | first magnitude |
Before telescopes, the dimmest star in the sky was called | sixth magnitude |
Apparent magnitude | how bright a star looks |
Absolute magnitude | actual temperature |
HR diagram | shows relationship between a star's temperature and absolute magnitude |
blue stars expand into | giants or supergiants |
main sequence | where stars spend most of their lives |
white dwarfs | small, hot stars that are the leftover centers of old stars, near the end of life |
nebula | large cloud of gas and dust in space |
gravity causes a nebula to | condense (squish), get hot and create the core |
nuclear fusion | when hydrogen joins with hydrogen, helium and hydrogen + a lot of energy |
When nuclear fusion begins | a star is born |
Young stars have a lot of | hydrogen |
Older stars have less hydrogen and more | helium |
When most of hydrogen fuel is gone, the outer layer of gas begins to expand, cool and glow red- called | Red (super) giant |
When a red giant uses up most of its hydrogen and helium, gravity squishes the star, and it gets hotter-called | White dwarf |
No energy, heat or light just a small, dense, cold lump called | Balck Dwarf or Cold Star |
supernova | a massive star that may explode in a flash of light |
Death of a large star by explosion happens when | outer layers collapse too quickly |
neutron star | some exploded particles pull together |
pulsar | spinning neutron star |
black hole | after a supernova particles clumped together to size of small point- even light |