The Saga of Eta Carinae

It WILL Go Boom… Sometime…

I am continually fascinated several regions of the sky. One of them is the Orion Nebula, where stars are being born. Another is the planet Mars, where I had sorta hoped I might get to explore in person someday.  Yet another is the Andromeda Galaxy — the closest spiral neighbor to our Milky Way.  And, yet another is the Carina Nebula, which is visible in southern hemisphere skies.

The Carina Nebula is a huge cloud of gas and dust located somewhere between 7,000 and 10,000 light-years away from us in the direction of the constellation Carina.  If you’re an astronomer studying the ephemera of star life, such as star birth and star death (both of which pass relatively quickly in the long span of a star’s existence), then Carina has something for you to look at.  There are star birth regions, where hot young stars (and maybe planets?) are forming as we speak.  There are dark dust blots that could contain the seeds of stars that are just starting to form. And, there are stars that are dying.

Eta Carinae as imaged by the Gemini South telescope in Chile with the Near Infrared Coronagraphic Imager (NICI).

Specificially, there’s eta Carinae, which is the most luminous star in our galaxy and is just one massive explosion away from becoming a supernova. In fact, it could be such a powerful explosion, it could be what astronomers often refer to as a “hypernova.”  Astronomers think it’s going to go blooey! any time now — well, in astronomical terms, “any time” could mean tomorrow or it could happen in the next few thousand years.

Eta Carinae has been under a lot of observation for the past century and a half. It brightened unexpected in 1843 and stayed bright for about 20 years before fading down. It has probably done this a number of times before and since then, and that intense “flickering” is a clue to its death throes. We don’t often get to see stars this late in their lives. So, this presents astronomers with a good chance to study what hugely massive stars do as they thrash around on their deathbeds: they expell gas and dust, they brighten and dim, and they send powerful jets of material out to space. When eta Carinae does go, it’ll be bright and messy. The nebula will be affected, and our skies will have a bright new star for  months.

This month’s segment of The Astronomer’s Universe (in the player below) on Astrocast.TV takes a look at the latest images and ideas about the Carina Nebula and the activities of its crotchetiest stellar member. Check it out!  And, don’t forget to watch Our Night Sky and A Green Space, A Green Earth, also on Astrocast.TV.