Question

The distance from Earth of the red supergiant Betelgeuse is approximately 643 light-years. If it were to explode as a supernova, it would be one of the brightest stars in the sky. Right now, the brightest star other than the Sun is Sirius, with a luminosity of 26LSun and a distance of 8.6 light-years.

Answer 1

Answer: The brightness of our if betelgeuse were to explode as as a supernova would by getting the ratio betelgeuse to sirius. Which would then be:

Apparent brightness of Betelgeuse

÷ Apparent brightness of Sirius=

6.9×10^4 Lsun.