| A | B |
|---|
| sun, Sol, Helios | our local small-mass, yellow dwarf, G2 class, main sequence star |
| star | most common, known astronomical object that produces energy/light by nuclear fusion |
| hydrogen fusion | nuclear fusion found in ordinary stars, where 4 hydrogens are fused into 1 helium + energy |
| hydrogen/helium | basic composition of stars, where hydrogen is the "fuel" and helium is the "byproduct" |
| core burning | nuclear fusion in the core of a star |
| nucleosynthesis | the process of element creation in a stellar core due to fusion |
| Hertzsprung-Russell (H-R) diagram | a classification plot of stars by spectral class (temperature) vs luminosity (energy output) |
| spectral class | grouping of stars by their spectral characteristics reflecting temperature variation |
| nebular theory | star formation theory starting with an interstellar nebula |
| nebula | interstellar cloud of gas and dust |
| protostar | astronomical object that is forming and may become a star, if enough mass is available |
| gravity collapse | the accumulation of interstellar gas and dust into a protostar |
| failed star | a protostar with not enough mass to start fusing H, a brown dwarf |
| brown dwarf | a failed star, with a mass less than 8% of a solar mass, or less than 85x of Jupiter's mass |
| main sequence star | a star located on the central band on a H-R diagram, considered stellar "adulthood" stage of evolution |
| stellar adulthood | evolutionary stage of stars that starts at H fusion in a star's core |
| small-mass star | a star with a mass between .08 and a few solar masses |
| dwarf star | a star similar in size to the sun or smaller |
| red dwarf | main sequence star that is small, cool, and faint |
| yellow dwarf | a main sequence star with a mass of 1 solar mass |
| medium-mass star | a star with a mass between several and 8 solar masses |
| subgiant star | a star larger than the sun and up to 10x larger in size |
| large-mass star | a star with a mass from 8 solar masses and higher |
| giant star | a star between 10x and 100x larger than the sun in size |
| supergiant star | a star greater than 100x the size of the sun |
| blue giant | main sequence star that is large, hot and bright |
| blue supergiant | main sequence star that is the largest, hottest and brightest |
| stellar old age | evolutionary stage of stars that starts at H fusion as a shell surrounding an ash core |
| shell burning | fusion in a star's interior surrounding a nonfusing core |
| ash core | the nonfusing core during shell burning |
| red giant region | the upper right area of an H-R diagram, where old-age, large, cool but bright stars plot |
| red subgiant | an old-age, red giant region star less than 10x the size of the sun |
| red giant | an old-age, red giant region star between 10x and 100x the size of the sun |
| helium flash | the point in small-mass, old-age, red giant region star when helium-core fusion starts |
| yellow giant | a small-mass, old age, red giant region star with stable helium-core and hydrogen-shell fusion |
| red supergiant | an old-age, red giant region star more than 100x the size of the sun |
| multiple shell burning | heavy element fusion steps in a large-mass, old-age, red giant region star |
| stellar death | the evolutionary end by explosion of an old-age, red giant region star |
| stellar remnant | the astronomical object that remains after an old-age star explodes |
| planetary nebula | the ejected outer layers of a small-mass, old-age, red giant region star as it dies |
| white dwarf region | the lower left area of an H-R diagram, where stellar remnant that are small, hot but dim stars, plot |
| white dwarf | the small, hot but dim stellar remnant that remains after a medium- or small-mass red giant region star dies |
| helium white dwarf | the stellar remnant of a small-mass red giant |
| carbon white dwarf | the stellar remnant of a medium-mass red giant |
| black dwarf | a cooled, solitary white dwarf stellar remnant |
| nova | the sudden increase in brightness of a white dwarf, due to surface fusion explosions |
| supernova | a very large and bright, destructive explosion of a star |
| supernova Type I | the catastrophic explosion of a carbon white dwarf star that gains mass to reach 1.4 solar masses |
| carbon detonation supernova | a supernova Type I that lacks a hydrogen signature |
| iron core collapse | the dying event of a large-mass, old-age red giant region star when it attains iron-core fusion |
| supernova Type II | the catastrophic explosion of a large-mass, old age, red giant region star at iron core collapse |
| core collapse detonation | a supernova Type II that has a hydrogen signature |
| supervova remnant | the ejected outer layers of a large-mass, old-age, red giant region star as it explodes |
| neutron star | stellar remnant between 1.4 and 3 solar masses that forms during a supernova Type II |
| pulsar | a star with a "pulsating" appearance interpreted to be a rapidly rotation neutron star |
| black hole | an area in space in which gravity is so strong that no light or radiation is received |
| stellar black hole | a black hole that forms when a supernova Type II leaves a 3 solar mass or larger stellar remnant |
