Q&A: Normal Stars, White Dwarf Stars, and Star Clusters

Q:
Why do astronomers think Eta Carinae will explode any time? If it explodes, how bright would it be? What will remain after it explodes?

A:
Astronomers think Eta Carinae COULD (not will) explode at any time because it is one of the most massive stars known. Its mass is estimated to be about 100 times the mass of the Sun -uncertain because Eta Car is shrouded in dust, and may be a binary system. Such a massive star will use up its nuclear fuel in only a few hundred thousand years. We don't know how old Eta Car is, but if it is a few hundred thousand years, it could explode at any time.

No one is sure what happens when such as massive star explodes, but if it is like the brightest of supernovas, it should be about a tenth as bright as the full moon!