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
Fleming 1 a torus of expanding hot gas forming the inner bright ellipse. Fleming 1 is probably 5,000 years old. Like any other planetary nebula Fleming 1 was formed when an old asymptotic giant branch (AGB) star lost its outer hydrogen-rich envelope, leaving behind a hot core (young white dwarf)—the central star of the nebula. The star in the center of Fleming 1 has a temperature of and mass of 0.56 . Observations performed by European Southern Observatory showed that the central star is in fact a double degenerate (made of two white dwarfs) binary with a period of days. The companion