SN 2009ip

[Terry Bohlsen]

Dear All
I was able to take a spectra of this now probable type II SN last night. It was at mag V=13.8
Data is here
http://users.northnet.com.au/~bohlsen/Nova/sn2009ip.htm

Cheers

Terry Bohlsen

[Francois Teyssier]

Hello Terry,

Nice spectrum of a very peculiar object.

Did you send it to Lastest Supernovae web site ?

All the best,

François Teyssier

[Robin Leadbeater]

Hi Terry,

Nice result

I have been playing with GELATO which is an automated supernova classification system. I tried it with your spectrum and it confirms it as type IIn (see attached screen shot) The comparison spectra do not show the emission line seenin your spectrum at 6855 though

Cheers
Robin

[Terry Bohlsen]

Robin
There is another spectra published here that shows the emission lines as He I lines.

[Robin Leadbeater]

Hi Terry,

Yes I can see signs of He, particularly at 5908A for example but the line I am talking about seems to be absent in the SALT spectrum too, though possibly buried in the Telluric band there, see attached

Cheers
Robin

[Terry Bohlsen]

Dear Robin
I looked into the line you mentioned. It is an artifact. It was a CRH on my last subexposure and I have edited it out and corrected the fit file on my webpage.
Now the info is on a Astronomers Telegram.
http://www.astronomerstelegram.org/?read=4477

[Francois Teyssier]

Good job Terry, congratulations for ATEL publication

Here's the abstract on a recent publication about this fascinating object

Some reports of supernova (SN) discoveries turn out not to be true core-collapse explosions. One such case was SN 2009ip, which was recognized to be a luminous blue variable (LBV) eruption. This source had a massive (50-80 Msun) hot progenitor star identified in pre-explosion data, it had documented evidence of pre-outburst variability, and it was subsequently discovered to have a 2nd outburst in 2010. This same source rebrightened again in 2012, and early spectra showed the same narrow-line profiles as before, suggesting another LBV-like eruption. We present new photometry and spectroscopy of SN 2009ip, indicating that its 3rd observed outburst in under 4 years appears to have transitioned into a genuine SN. The most striking discovery in these data is that unlike previous reports, the spectrum exhibited Balmer lines with very broad P-Cygni profiles characteristic of normal Type II supernovae (SNe II), in addition to narrow emission lines seen in SNe IIn and LBVs. Emission components have FWHM 8000 km/s, while the P-Cygni absorption component has blue wings extending to about -13,000 km/s. These features are typical of Type II SNe, but have never been seen in a nonterminal LBV-like eruption. Initially, the peak absolute magnitude of M_V \sim -14.5 seemed fainter than that of normal SNe and faded much more rapidly. However, the source quickly brightened again to M_R=-17.6 mag, indicating that it is indeed consistent with a true SN. In this bright phase, the broad lines mostly disappeared, and the spectrum became dominated by broad-winged Lorentzian profiles of H-alpha and HeI that are characteristic of the early optically thick phases of luminous SNe IIn. We conclude that the most recent 2012 outburst of SN 2009ip is most likely a true core-collapse SN IIn that was initially faint, but then rapidly achieved high luminosities, as a result of interaction with circumstellar material (abridged).

http://arxiv.org/abs/1209.6320

François

[Terry Bohlsen]

I took a follow up spectra last night. No change really
see
http://users.northnet.com.au/~bohlsen/Nova/sn2009ip.htm