will earth be destroyed by sirus B`s sometime disstant future supernova and what are the chances?

Question

OK i read some stuff on the internet but cant remember what they are

Answer 1

Sirius B is a white dwarf. These don't supernova until their binary stars become red giants, which Sirius A isn't. By the time it does, it will have drifted thousands of lighyears away. There is a much greater chance we will be hit by an asteroid or a supervolcano before then.

Answer 2

No. In fact Sirius B will never supernova. The white dwarf Sirius B orbits Sirius A at a distance of ~19.8 astronomical units. With an estimated mass of 0.98 M_sun and Sirius A with an estimated mass of ~5 M_sun, the L1 lagrange point is approximately 13.7 astronomical units from the center of Sirius A.

This is the "magic point" at which the gravitational pull on a line between the two stars is equal. This is the radius to which Sirius A would have to swell during its red giant phase to effect mass transfer to Sirius B, increasing its mass and *possibly* generating a supernova when it reaches the Chandresekhar limit mass of 1.4 M_sun.

This is well beyond the orbit of Saturn. No red giant reaches this size, least of all a star with a progenitor mass of only 5 M_sun.

Sirius A itself will not supernova because its mass is well below the estimated minimum supernova progenitor mass of 8 M_sun.

That said, at the current distanct of Sirius, I estimate a supernova would appear roughly 1,000 times as bright as the sun for a day or so (1.5 MW/sq meter) which I suppose would make things nasty on the parts of earth exposed, and rather difficult on the rest, but still, only one day probably looks like a mass extinction event rather than a sterilization event.