Explosion with the mass of Chandrasekhar

In the case of the simply degenerated models, the significant parameter is the accretion rate. An explosion takes place only if this accretion rate has a relatively precise value. In particular, if one exceeds a breaking value (), there is formation of a layer common to both stars which can involve a gravitational collapse. On the other hand, if this accretion rate is below a certain value, there is appearance of nova which involves losses of mass higher than the accrétée mass. For a little higher rates, there is appearance of a layer of helium which involves flashes. This difficulty seems to be solved by the taking into account of the stellar wind. It seems, indeed, being an essential phenomenon to see the dwarf white one reaching the mass of Chandrasekhar.

$$\dot M_c = 0.75 .10^{-6}(\frac{M_{NB}}{ \rm\, M_\odot } -0.40) \rm\, M_\odot .y^{-1}$$ (5.20)

is the accretion rate for which a static burning takes place on the surface of dwarf white. When the accretion rate reaches this value, the dwarf white one dilates to reach $0.1 \rm \, R_\odot$. If the wind is sufficiently strong, it can prevent the formation of the common envelope. The fusion of hydrogen makes it possible to increase the mass of dwarf white. This fusion involves an increase in the layer of helium. When this layer reaches a limiting mass, there is appearance of a helium flash. A fraction of this layer is then puffed up but a substantial part is converted into carbon and oxygen to increase the heart of dwarf white.