[renormalised (Carl)]

No, it's only 2 solar masses. Stars need to be between 8-11 before they're big enough to go off as supernovae. Why the size range??. Depends on what happens to the stars of that size late in life...specifically, how much mass they have left over after the AGB stage. If the core accumulates more than 1.4 solar masses of material, then they're destined to become supernovae. If it falls short, then you get a rare type of white dwarf called a Oxygen-Neon White Dwarf...very small, very heavy.

I don't think Sirius B is in a tight enough orbit to be collecting mass from Sirius itself (it's a 50 year orbit), but if it was, and it was collecting it at a high enough rate, then you could get a Type I supernova going off. If it went off tomorrow, we'd be toast...literally.