Red supergiant star to individual objects, but it may become useful for analysis of galactic structure and discovery of otherwise obscured red supergiant stars. Surface abundances of red supergiants are dominated by hydrogen even though hydrogen at the core has been completely consumed. In the latest stages of mass loss before a star explodes, surface helium may become enriched to levels comparable with hydrogen. In theoretical extreme mass loss models, sufficient hydrogen may be lost that helium becomes the most abundant element at the surface. When pre-red supergiant stars leave the main sequence, oxygen is more abundant than carbon at the surface, and
Sudarsky's gas giant classification to reflection by the cloud decks. At such temperatures, a gas giant may glow red from thermal radiation but the reflected light generally overwhelms thermal radiation. For stars of visual apparent magnitude under 4.50, such planets are theoretically visible to our instruments. Examples of such planets might include 51 Pegasi b and Upsilon Andromedae b. HAT-P-11b and those other extrasolar gas giants found by the Kepler telescope might be possible class V planets, such as Kepler-7b, HAT-P-7b, or Kepler-13 b. Sudarsky's gas giant classification Sudarsky's classification of gas giants for the purpose of predicting their appearance based on their temperature