Friday, December 4, 2009

'She Blowed Up REAL Good ...!'

Eta Carinae
This week the Sky & Telescope website gives us not one but two chances to indulge in gratuitous astronomical violence.

The first is a supernova detected in a remote galaxy in 2007, estimated to be about 100 times more powerful than mere 'ordinary' supernovae. A star of about 150 to 240 solar masses blew itself entirely apart. No remnant neutron star, no black hole, no nothing, just the expanding fireball.

They don't make bangs like that in our galaxy any more, not for the last few billion years. To get them you need stars of enormous mass that form only in the first generation, when there are no elements heavier than helium. The observed supernova is probably in a dwarf galaxy only just now forming stars. In our part of the universe the only remnants of these high power blasts are ... us. (And planets, etc.)

But our home galaxy is still perfectly capable of lesser bangs from conventional supernovae, and a prime candidate is Eta Carinae. In the 19th century it flared up for several decades to become one of the brightest stars in the sky, then faded to 5th magnitude. The Hubble image tells the story: a vast eruption, its expanding cloud now partly concealing the massive binary star within.

Evidence points to 'a new unstable phase of mass loss,' which sounds duly ominous. And all you have to do is look at the image to see that Eta Carinae, like a bad girl in a Victorian novel, is heading for a tragic but spectacular fate.

Related post: Betelgeuse is also living on borrowed time.


Jean Remy said...

A possible 100 stellar mass star potentially going supernova in our lifetimes!

Get the lawn chairs ready, this one is going to be good.

By the way, two massive stars orbiting at less than 1 AU from each other has to be pretty impressive. I wonder what will happen to the "survivor" of that couple, but I am not assuming anything good.

Rick said...

Book your tickets to Oz. Eta Carinae is pretty far south, mostly invisible in the northern hemisphere, but high in the southern sky.

So far as I can tell, nothing all that bad happens to the survivor. It may become a 'runaway' star, hurtling off into the void at its formal co-orbital speed.