Advertisement Upgrade to remove ads


The creation of energy by joining the nuclei of two hydrogen atoms to form helium.


How bright a star will be in relation to the sun


Another word for brightness


The lowest layer of the Sun's atmosphere and the layer that gives off light


A thin layer of the sun's atmosphere between the corona and the photosphere; too faint to see unless there is a total solar eclipse


The outer layer of the sun's atmosphere; looks like a crown around it during a solar eclipse


A dark area of gas on the sun that is cooler than surrounding gases

H-R Diagram

Hertzsprung-Russell diagram, a graph that shows the relationship between a star's surface temperature and absolute magnitude


A large cloud of gas and dust in interstellar space; a region in space where stars are born

Black Hole

Remnant of a star that is so dense that nothing, not even light, can escape its gravity field.


The brilliant explosion of a dying supergiant star

Neutron Star

The collapsed core of a supernova whose dense core has only neutrons

White Dwarf

The blue-white hot core of a star that is left behind after its outer layers have expanded and drifted out into space

Supergiant Star

The largest star yet has the shortest lifespan; about 1000 times the diameter of sun

Giant Star

A large star with great luminosity and a diameter 10 to 100 times greater than that of the sun


A group of stars that form a pattern in the sky


Small groups of stars that form a pattern within constellations


A term describing a star that neither rises nor sets but appears to rotate around one of the celestial poles.


The central region of a star, where nuclear fusion takes place

Solar Flares

Violent eruptions of particles and radiation from the surface of the Sun


A loop of gas that protrudes from the sun's surface, linking parts of sunspot regions

Solar Wind

A stream of electrically charged particles that come from the sun's corona


Early form of a star; This stage lies between the collapsing of dust and gas and the beginning of nuclear fusion

Main Sequence

A band of stars that includes most stars of average color, size, magnitude, and temperature

Convective Zone

The region of the sun's interior that is between the radiative zone and the photosphere and in which energy is carried upward by convection

Radiative Zone

The middle zone of the sun's interior where thermal energy moves outward from the core by radiation

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording