Red Giant

A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses (M)) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower. The appearance of the red giant is from yellow-orange to red, including the spectral types K and M, but also class S stars and most carbon stars.

The most common red giants are the so-called red-giant-branch (RGB) stars whose shells are still fusing hydrogen into helium in a shell surrounding a degenerate helium core. Other red giants are: the red clump stars in the cool half of the horizontal branch, fusing helium into carbon in their cores via the triple-alpha process; and the asymptotic-giant-branch (AGB) stars burning a helium shell outside a degenerate carbon–oxygen core, and sometimes also a hydrogen shell closer to the surface of the star.

The nearest red giant is Gamma Crucis, 88 light years away, but the orange giant Arcturus is described by some as a red giant and it is 36 light years away.

Read more about Red GiantCharacteristics, Evolution, Well Known Examples, The Sun As A Red Giant

Other articles related to "giant, red giant, red":

Giant Stars - Formation
... A star becomes a giant star after all the hydrogen available for fusion at its core has been depleted and, as a result, it has left the main sequence. 0.25 solar masses will not become a giant star ... Eventually the star will start to ascend the red giant branch on the Hertzsprung–Russell diagram ...
List Of Astronomy Acronyms - R
... from the survey RC – (celestial object) Red Clump, a type of metal-rich red giant star also RCG – Red Clump Giant RC – (catalog) Reference Catalogue ... University RSG – (celestial object) Red Super Giant RSN – (celestial object) Radio SuperNova RTG – (instrumentation) Radioisotope Thermoelectric Generator, a type of ...
RS Ophiuchi
... is produced by a white dwarf star and a red giant circling about each other in a close orbit ... About every 20 years, enough material from the red giant builds up on the surface of the white dwarf to produce a thermonuclear explosion ... The white dwarf orbits close to the red giant, with an accretion disc concentrating the overflowing atmosphere of the red giant onto the white dwarf ...
The Sun As A Red Giant
... The evolution of the Sun into and through the red-giant phase has been extensively modelled, but it is still unclear whether the Earth will be engulfed by the Sun or will, barely, survive ... At its brightest, the red-giant Sun will be several thousand times more luminous than today despite being around half the temperature ...
BD Camelopardalis
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