m95 Nova

In between clouds took these:

This evening I managed to capture some spectral data of supernova 2012aw covering the range from 4000angstroms to 8500 angstroms. The attached image is just a first output and is not corrected for instrument response. However it shows quite clearly a couple of interesting features. There is a clear P-Cygni profile developing around the H-Alpha line. Evidence too of classic H-balmer series lines emerging from the continuum. I also see evidence of Sodium absorption which when compared to SNe 1992H (A.V.Fillipenko) seems a little early (with 1992H Sodium absorption became prominent at T+73days) . Ca II absorption is also prominent.

I will of course follow up with an response corrected profile, but for now I thought this was worth sharing.

Equipment: C14, Star Analyser+Prism, SBIG-ST8 27x120sec stacked

Please See: www.webtreatz.com/images/2011aw.jpg for full sized image.

Dave

Thanks for sharing that.

Spectroscopy is an extremely important branch of astronomy and our population, being small, means that you are probably pushing the envelope for our amateur community. I, for one, would appreciate any analysis that you post on your spectroscopic measurements.

Please do point out distinguishing features of observations worthy of comment and why they are so.
I think many of us (initially) will not appreciate what is being reported - but if we receive multiple reports it might well gel in time.

The same, I believe, is true of solar observation reports.
Most of the time time I can't see the value (my ignorance) - but realise that given enough exposure they will become meaningful.

Regards

Mark C.

Hi Mark,

Yes you are right of course, in my excitement early this morning, I didn't go into nearly enough plain english about why spectra like these are important and what they mean.

I'm afraid I just re-used text from an e-mail which I had e-mailed to some other spectroscopy enthusiasts, so I apologise for the lack of explanation in my original post.

The really interesting thing here is the previously mentioned -"P-Cygni" profile. This is labelled in the spectrum as Ha. What were looking at here specifically is hydrogen rushing both toward and away from us. The huge velocities involved means the H which is coming toward us is being 'blue-shifted' to the left (represented by the dip) and the material going away is red-shifted (to the right and represented by the peak). Normally (in P-Cygni profiles) of non-exploding stars, the P-Cyngi profile would be no where near this wide, however the incredibile velocities here means that the profile is widened dramatically.

The H gamma and h delta lines marked are also interesting. These are known as part of the Hydrogen-Balmer series lines. Only type II events have these. So given the obvious p-cygni profile we can see from this that that a:) there is lots of hydrogen and b:) there is material rushing away from the event at collossal speeds. Therefore we can see that this is a type II supernova. Professionals would use larger scopes and higher res spectra to further sub-categorise.

Here's the cool bit. The massively expensive and horribly complex spectrograph used to capture the above is simply a £100 'Star-Analyser'. I did add a small wedge prism to the front of the SA to give me a 'grism' arrangement grism = grating + prism. I do own a higher res instrument, and hope to get a close up of that p-cygni profile soon. With this higher-res it may be possible to measure the speed of the outflow and perhaps put a size on the progenitor star. I think that would be really cool.

Hopefully this explanation makes the above more meaningful.

Dave.

Thanks very much for that very well explained analysis.
I'm very impressed with the results that such a simple setup is capable of producing.

Best regards

Mark C.