SN2006gy and Eta Carinae Update

In my previous post about SN2006gy there were several references to the similarity between the progenitor star and Eta Carinae. The similarities are starting to get some play in the popular press, but I’m not convinced that Eta Car. and the SN2006gy progenitor were all that much alike.

First of all, there’s some evidence that Eta Car. might be a double. It’s hard to tell with all that stuff in the way, but the X-Ray source inside the obscuring nebula is eclipsed every 5.5 years for about 3 months.

Second, it is difficult to tell what the exact metallicity of SN2006gy was; the assumption is that it was a low metallicity star, where Eta Car. is probably higher in that aspect.

So there’s a buzz that Eta Car. could go supernova at any moment… well, that’s true enough, but it probably won’t be another pair-production instability supernova like SN2006gy. Those events are apparently very, very rare.