Will Sirius B ever become a supernova?
A very good question. We do not really know why some white dwarf systems become Type I supernova, but the minimum requirement is that the normal companion star not be too far away and that it be an evolved red giant star shedding mass. Some of this mass is collected by the white dwarf pushing it over the stable mass limit of 1.4 solar masses for a white dwarf. It then collapses into a neutron star or a black hole producing a supernova. Now, Sirius B is just under 1 solar mass, and it is located about 23 Astronomical Units (AUs) from Sirius A with a 49 year period. Sirius A is a main sequence A1 star with a mass of 2.3 time the sun.
My impression is that once Sirius A becomes an ordinary red giant, its outer layers will probably not extend more than a few AU and Sirius B will be well outside the atmosphere of Sirius A. I do not see how this would be favorable for a supernova, but it could be a nova from time to time. Good for a few flare ups every few hundred years or so!!
Return toAsk the Astronomer