Red+Supergiants+4A

-Red supergiants span several hundred times the diameter of the sun. -The red supergiant phase is short it only lasts from a few hundred to a million years or so. -After helium-burning red giant runs out of helium in its core, the star's core starts to collapse and heat up. -After the star runs out of hydrogen fuel, the star swells larger and larger and it becomes a red supergiant. -Spectral type K-M -Luminosity class of 1 -The zone of hydrogen fusion continually moves outward leaving behind a helium core. -Usually end in a super nova -Only 200 are known in the entire galaxy
 * Red SuperGiants**

//Cluster of red supergiants// -Found a massive cluster of about 20000 stars classed RS0C1, which include 14 red supergiants.

Betelgeuse -Makes up the right shoulder of the constellation Orion -425 light years away -It has a radius of 800x's more than our sun. -Best-Known supergiant -Surface tempature of 3000K -Betelgeuse is 310 light years away from earth



4 Largest Supergians known -Mu Cephei -KW Sagitarii -V354 Cephei -KY Cygni -They are 1500 x's the radius of our sun