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View Full Version : Boom! Boom! Kaboom! KERSPLOSION!!!!



Don Alexander
2012-Sep-27, 10:06 PM
Okay, sorry for the silly title, but I have another cool piece of astronomical news to report.

So, most of you will likely have heard of Eta Carinae and it's Great Eruption 150 years ago. The star became the second brightest star in the night sky, ejected multi-solar masses of matter, and yet survived. The star is a Luminous Blue Variable (LBV), and these undergo massive eruptions every once in a while.

Six years ago, a supernova, SN 2006jc, was discovered (http://arxiv.org/abs/astro-ph/0703663), which had been seen to already erupt, though at a significantly fainter magnitude, two years earlier. It seemed such violent LBV eruption may be the precursors to real SNe!

A few years ago, what was initially classified as a supernova, SN 2009ip, turned out to be another "supernova impostor" (see Smith et al. (http://arxiv.org/abs/0909.4792) and Foley et al. (http://arxiv.org/abs/1002.0635)). In contrast to 2006jc, it was seen to erupt multiple times in earlier archival data, and it was seen to erupt again in 2010 (http://www.astronomerstelegram.org/?read=2897).

Recently, another LBV outburst was reported (http://www.astronomerstelegram.org/?read=4334). So far, so "standard", it looked the same spectroscopically as well (http://www.astronomerstelegram.org/?read=4338).

Until Smith & Mauerhan (http://www.astronomerstelegram.org/?read=4412) reported a new spectrum that showed much broader spectral lines, which indicated the star had really gone supernova!!! The next reports showed it to be dimming, though (http://www.astronomerstelegram.org/?read=4414), evidence in contrast to the SN theory (http://www.astronomerstelegram.org/?read=4338).

It was an amateur astronomer (http://www.astronomerstelegram.org/?read=4423) who then found that after this dimming, the source brightened by several magnitudes (up to six magnitudes in the UV! (http://www.astronomerstelegram.org/?read=4425)) in just a few days, and to mags much brighter than the LBV outbursts.

New spectroscopy (http://www.astronomerstelegram.org/?read=4427) shows a further transition to narrow emission lines, a characteristic signature of a Type IIn supernova driven by interaction with circumstellar material. NIR spectroscopy (http://www.astronomerstelegram.org/?read=4431) also confirms this interpretation.

So, to summarize: We have been watching a massive star in another galaxy become more and more unstable, and we were watching pretty much the moment the thing finally blew up completely!!! Now, if that isn't awesome, I don't know what is...

Looking forward to the next Nathan Smith Nature paper. :whistle:

Tensor
2012-Sep-27, 10:49 PM
Okay, sorry for the silly title, but I have another cool piece of astronomical news to report.

Silly titles or not, it's always a treat when I see a new post by you. Just want you to know your posts here are very informative and very appreciated.

slang
2012-Sep-27, 11:25 PM
Okay, sorry for the silly title

Heh, it's ok if you deliver.. and that you never fail :)

You always make me want to read all the links... alas I rarely find the time to do so :/

Don Alexander
2012-Sep-28, 12:22 AM
Well, well, just hours later, Mauerhan, Smith et al. publish their paper!!! (http://arxiv.org/abs/1209.6320) :clap:

I was wrong. It's not Smith et al., and it's not Nature! :o

Cougar
2012-Sep-28, 01:56 AM
So, to summarize: We have been watching a massive star in another galaxy become more and more unstable, and we were watching pretty much the moment the thing finally blew up completely!!!

That is great. That's the ultimate in a Variable - it goes from being something to being nothing.


Well, well, just hours later, Mauerhan, Smith et al. publish their paper!!!

What an informative abstract! Yes, that's pretty hot off the press!

antoniseb
2012-Sep-28, 10:52 AM
Wow! This is a cool story. Thanks again!

http://arxiv.org/abs/1209.6155 This is Nathan Smith's solo paper.

Don Alexander
2012-Sep-28, 11:46 AM
But that one has no direct relationship to SN 2009ip, furthermore, it seems to be a revised version, so likely submitted before the true SN 2009ip was discovered.

Don Alexander
2012-Oct-12, 09:39 PM
Vinko et al. (http://www.astronomerstelegram.org/?read=4479) now report renewed spectral broadening, the true SN ejecta has caught up and is breaking through the shells ejected in the last few years.

EDIT: And now they have retracted that again... (http://www.astronomerstelegram.org/?read=4480) :(

Don Alexander
2012-Oct-16, 10:06 AM
Two additional papers have been uploaded to the arXiv:

Prieto et al.: The Rise of the Remarkable Type IIn Supernova SN 2009ip (http://arxiv.org/abs/1210.3347)
Pastorello et al.: Interacting Supernovae and Supernova Impostors. I. SN 2009ip, is this the end? (http://arxiv.org/abs/1210.3568)

Furthermore, Mauerhan et al. have posted an updated version of their paper with additional data. (http://arxiv.org/abs/1209.6320v2)

George
2012-Oct-18, 03:35 AM
The volatility is exciting at all levels. Appropriate title, IMO. :)

How bright might it get?

StupendousMan
2012-Oct-18, 11:56 AM
How bright might it get?

Well, the host galaxy NGC 7259 has a distance (based on redshift only, so not great) of around 25 Mpc. The distance modulus is about 32 magnitudes. So, if this supernova reached a "typical" Type II peak absolute magnitude of M = -18.5, the apparent magnitude would be (-18.5 + 32) = 13.5. If this event turns out to be more luminous than most, due to the interaction of the ejecta with material from earlier stellar winds (as seems likely), it might reach, if really bright, M = -21, which would cause the apparent magnitude to be (-21 + 32) = 11.

None of the values above take into account extinction; there is likely to be little due to the Milky Way, but there could be plenty due to the host galaxy or due to mass loss from the progenitor itself.

Actual measurements from Dave Bishop's site

http://www.rochesterastronomy.org/sn2009/sn2009ip.html

give current apparent magnitude values of around 13.5.

Don Alexander
2012-Oct-18, 12:47 PM
It seems to have peaked already according to the latest published light curves. Somewhere around 13th magnitude, I think. That's far below binocular range, but in easy range of amateur CCD imaging, and will place it among the top ten brightest SNe this year (likely). In terms of absolute magnitudes, it was in the range of -18, which is "run of the mill" for SNe.

George
2012-Oct-18, 04:02 PM
Thanks for the mag. estimates.