Changes

==Hypergiants==

==Hypergiants==

The stars with the greatest luminosity and mass are generally referred to as '''hypergiants''' (luminosity class 0).  Although the term is used loosely, the criterion used to separate supergiants from hypergiants is that the latter are stars with an absolute magnitude greater then -7.  Because of this, hypergiants do not have to be the more massive than other supergiants, but the most massive stars are still generally seen as hypergiants.<ref>http://adsabs.harvard.edu/abs/1998A%26ARv...8..145D</ref> Like supergiants, these most luminious of stars can have a spectral type ranging from class A to M.

The stars with the greatest luminosity and mass are generally referred to as '''hypergiants''' (luminosity class 0).  Although the term is used loosely, the criterion used to separate supergiants from hypergiants is that the latter are stars with an absolute magnitude greater than -7.  Because of this, hypergiants do not have to be the more massive than other supergiants, but the most massive stars are still generally seen as hypergiants.<ref>http://adsabs.harvard.edu/abs/1998A%26ARv...8..145D</ref> Like supergiants, these most luminious of stars can have a spectral type ranging from class A to M.

Hypergiants are so luminous that they sit very close to the point where radiation from the interior of the star would overcome the inward force of gravity.  This theoretical upper limit for the luminosity of a star is called the '''Eddington limit'''.  Any star that exceeds this limit will be blown apart from its own immense radiation.

Hypergiants are so luminous that they sit very close to the point where radiation from the interior of the star would overcome the inward force of gravity.  This theoretical upper limit for the luminosity of a star is called the '''Eddington limit'''.  Any star that exceeds this limit will be blown apart from its own immense radiation.

==End of Supergiants==

==End of Supergiants==

All spectral types of supergiants can end their lives as [[supernova]] if their cores' mass exceed 1.4 solar masses (known as the [[Chandrasekhar limit]]).<ref>http://adsabs.harvard.edu/abs/1987ApJ...323..140L</ref>  It was once thought that only red supergiants could end their lives this way.  This was disproved with occurrence of Supernova 1987A in the [[Magellanic Clouds#Large Magellanic Cloud|Large Magellanic Cloud]] on February 23, 1987, when it was discovered the progenitor star was a B3 class, blue supergiant.<ref>http://adsabs.harvard.edu/abs/arXiv:0705.3066</ref>  Supergiants that have a core mass of less then 1.4 solar masses will end their lives as a [[white dwarf]].

All spectral types of supergiants can end their lives as [[supernova]] if their cores' mass exceed 1.4 solar masses (known as the [[Chandrasekhar limit]]).<ref>http://adsabs.harvard.edu/abs/1987ApJ...323..140L</ref>  It was once thought that only red supergiants could end their lives this way.  This was disproved with occurrence of Supernova 1987A in the [[Magellanic Clouds#Large Magellanic Cloud|Large Magellanic Cloud]] on February 23, 1987, when it was discovered the progenitor star was a B3 class, blue supergiant.<ref>http://adsabs.harvard.edu/abs/arXiv:0705.3066</ref>  Supergiants that have a core mass of less than 1.4 solar masses will end their lives as a [[white dwarf]].

==See also==

==See also==