Starship Asterisk*

There is a supernova in M65, SN 2013am, and I find it so interesting.
M65 is a quite red galaxy, with extremely little star formation. In Al Kelly's picture of M65, however, you can see a blue cluster at about 2 o'clock and a bluish "arc" of young stars "above" the cluster. Apparently the supernova is located close to this "arc" of young stars. Check out Efrain Morales' picture of M65 with SN 2013am here.

A galaxy so full of old stars, and so deficient in young stars, might be expected to produce a supernova type Ia. After all, almost all galaxies can be expected to contain white dwarfs, some of them in orbit around swollen red giants that white dwarfs can feed off of and gain mass. But if you enlarge Efrain Morales' image, you can see that the supernova appears to be non-blue. That suggests that it is not a supernova type Ia. And indeed, according to www.rochesterastronomy.org, SN 2013am is a supernova type II, a massive core-collapse supernova. But if so, the progenitor of SN 2013am must be a massive and therefore young star. And fascinatingly, the supernova exploded right next to one of the extremely few places in M65 where we find young stars. Note that no pink emission nebulae are visible in M65, so there appears to be no ongoing star formation there. But there are a few massive young stars there that are just old enough to start going supernova, and one of them exploded. Wow.
To fully appreciate how red M65 really is, and how deficient in young stars it is, please compare it with its galactic neighbour, M66. In Scott Rosen's image on the left, you can see how very yellow M65 is compared with M66, which contains large bright blue clusters and pink emission nebulae.

But one of the young stars that M65 almost doesn't have did go pop.

Ann

Here's a picture of the supernova.

It appears to be the first recorded supernova in M65, whereas its "neighbour" M66 has had at least two, SN 1973R and SN 1989B.


Ann

Ann, (or anyone else) Do you know what the naming convention is for supernovae? Clearly SN 2013 stands for supernova in year 2013 (!) but what does the 'am' refer to? On the Rochester site there is another supernova called 'SN 2013ar'.

Margarita

MargaritaMc wrote:Ann, (or anyone else) Do you know what the naming convention is for supernovae? Clearly SN 2013 stands for supernova in year 2013 (!) but what does the 'am' refer to? On the Rochester site there is another supernova called 'SN 2013ar'.

The letters following the year just indicate the order of discovery. "A" is the first, "B" the second, "Z" the 26th, "aa" the 27th, "ab" the 28th, and so on. So "am" is the 39th of 2013.

This may be of interest. Here is a link to the proposal that described that very thing. I would imagine, at the very least, personnel at The Queen's University of Belfast would be reviewing their data, saying AHA! One of the galaxies in that proposal was M 65!
http://archive.stsci.edu/proposal_searc ... st&id=9042

Chris Peterson wrote:

MargaritaMc wrote:Ann, (or anyone else) Do you know what the naming convention is for supernovae? Clearly SN 2013 stands for supernova in year 2013 (!) but what does the 'am' refer to? On the Rochester site there is another supernova called 'SN 2013ar'.

The letters following the year just indicate the order of discovery. "A" is the first, "B" the second, "Z" the 26th, "aa" the 27th, "ab" the 28th, and so on. So "am" is the 39th of 2013.

Thank you, Chris - that code would never have occurred to me. Nor that so MANY supernovae are discovered in any one year: 43( SN 2013ar?) so far in 2013 and we are only a quarter way through the year.
Margarita