Contents
The progéniteurs of the gravitational supernovæ are stars of great mass ( 
and more) at the end of the lifetime. The compensation of the pressure
of gas of the heart nourished by nuclear fusion and of the gravitation
makes it possible to maintain star in hydrodynamic balance. This
peaceful life is only disturbed by episodes during which the fuel
interns rarefies, involving a fall of the pressure of gas and a
beginning of gravitational collapse. This collapse causes an increase
in the temperature and pressure of the heart. It follows a lighting of
a new fuel (a heavier core which thus amalgamates at higher
temperature).
The sun will know this type of
transition in 3 to 4 billion years when it finishes burning its
hydrogen and starts to burn its helium to form carbon and oxygen. We
will detail more in details this stage of the stellar life in the next
chapter.
Contents Julien Raux 2004-05-04