Username:

Password:

UKAI is moving to Facebook

Author Topic: Supernova 2012aw: Spectrum.  (Read 6001 times)

0 Members and 1 Guest are viewing this topic.

Offline Dave Grennan

  • Full Member
  • ***
  • Posts: 347
    • Irish Astrophotography
Supernova 2012aw: Spectrum.
« on: 01:12:49, 26 March, 2012 »
This evening I managed to capture some spectral data of supernova 2011aw 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.
Regards and Clear Skies,

Dave.
------------------------------
http://www.webtreatz.com
14" f/3.8 Custom Newtonian, WO GT81 Refractor, AP1200 Mount, Atik 460EX, SBIG ST8-XME, Lodestar and a whole pile of other stuff!

Offline andrew s

  • Full Member
  • ***
  • Posts: 373
Re: Supernova 2012aw: Spectrum.
« Reply #1 on: 08:33:10, 26 March, 2012 »
Nice capture Dave.

Offline psjshep

  • Database dude... for the last breath of UKAI
  • Administrator
  • Galactic Poster
  • *****
  • Posts: 10209
  • My god! It's full of stars.... just often enough!
    • Some astro Pics
Re: Supernova 2012aw: Spectrum.
« Reply #2 on: 09:10:32, 26 March, 2012 »
Looks very "jazzy" - can you explain a few of those terms for us lesser-informed, non-spectrum knowing people?

Also, I would be interested in knowing how you captured your data?

Phil
--------------------------------------------------------------------------
Web Images

Offline Dave Grennan

  • Full Member
  • ***
  • Posts: 347
    • Irish Astrophotography
Re: Supernova 2012aw: Spectrum.
« Reply #3 on: 10:41:37, 26 March, 2012 »
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.

Scope is a C14.

If anyone has any questions, I'd be only too happy to answer (if I know ther answer!)

CS
Dave.
Regards and Clear Skies,

Dave.
------------------------------
http://www.webtreatz.com
14" f/3.8 Custom Newtonian, WO GT81 Refractor, AP1200 Mount, Atik 460EX, SBIG ST8-XME, Lodestar and a whole pile of other stuff!

Offline psjshep

  • Database dude... for the last breath of UKAI
  • Administrator
  • Galactic Poster
  • *****
  • Posts: 10209
  • My god! It's full of stars.... just often enough!
    • Some astro Pics
Re: Supernova 2012aw: Spectrum.
« Reply #4 on: 10:45:13, 26 March, 2012 »
Now THAT was an explanation  :clap:

Thanks for that Dave - very interesting.

Phil
--------------------------------------------------------------------------
Web Images

Online chris.bailey

  • Administrator
  • Galactic Poster
  • *****
  • Posts: 10012
  • If at last you do succeed, don't try again
    • Rosemount Observatory
Re: Supernova 2012aw: Spectrum.
« Reply #5 on: 13:57:52, 26 March, 2012 »
Very interesting indeed but I must profess to needing to google a whole load of it!
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline Nomis Elfactem

  • Administrator
  • Galactic Poster
  • *****
  • Posts: 13011
    • The View From A Room
Re: Supernova 2012aw: Spectrum.
« Reply #6 on: 14:24:21, 26 March, 2012 »
The massively expensive and horribly complex spectrograph used to capture the above is simply a £100 'Star-Analyser'. 

I just made everyone in the client office I'm currently working in look round as I just swore (I thought I did it in my head but obviously not by the reaction).  I had concluded that you'd got a very nice multi-thousand pound spectroscope  :duh: :urock:

I've been looking to get into Spectroscopy for some time and had wondered about starting off with a SA grating.... I think you've just answered the question.

Quote
I did add a small wedge prism to the front of the SA to give me a 'grism' arrangement grism = grating + prism. 

Can you give some more detail (and/or a picture)... would love to see the setup. Also what camera did you use and capture software (to convert the image into the line graph) ?

Also, I realise you have a C14 but can you manage my expectation on using a 102mm refractor ?  I realise it won't be anything remotely close to what you've got but is it worth a try or should I save my money and just feed my addiction off what you guys do ?

Cracking stuff Dave  :clap: :thumbup:
Simon

Scopes: Astro-Tech AT-111EDT Triplet, TS65ED Quad, Orion ST80, Modded PST-90 Solar Scope, PST Cak (on loan)
Cameras: SXVF H694, Atik 16ic, Canon EOS 600d, DMK41, DMK21, QHY 5L-II (mono & colour)
Accessories: SX USB Filter Wheel, SX OAG, Baader LRGB Ha SI OII Filters, SharpSky Focuser
Mount: EQ6 (EQMOD), SW Star Adventurer, plus a lot (and I mean a lot) of other bits and pieces

Offline andrew s

  • Full Member
  • ***
  • Posts: 373
Re: Supernova 2012aw: Spectrum.
« Reply #7 on: 15:05:22, 26 March, 2012 »
Simon and other who are interested have a look at this http://www.astrosurf.com/buil/staranalyser/obs.htm and bits available here http://www.shelyak.com/rubrique.php?id_rubrique=4.
Also Robins' home page (he developed the SA idea) http://www.threehillsobservatory.co.uk/astro/spectroscopy.htm

Andrew

Offline psjshep

  • Database dude... for the last breath of UKAI
  • Administrator
  • Galactic Poster
  • *****
  • Posts: 10209
  • My god! It's full of stars.... just often enough!
    • Some astro Pics
Re: Supernova 2012aw: Spectrum.
« Reply #8 on: 15:12:18, 26 March, 2012 »
Will the Star Analyser that Bern has,  do the biz?

http://www.modernastronomy.com/accessories.html   ( see 1/2 way down the page)

Phil
--------------------------------------------------------------------------
Web Images

Offline andrew s

  • Full Member
  • ***
  • Posts: 373
Re: Supernova 2012aw: Spectrum.
« Reply #9 on: 16:13:14, 26 March, 2012 »
Will the Star Analyser that Bern has,  do the biz?

http://www.modernastronomy.com/accessories.html   ( see 1/2 way down the page)

Phil

Yes - it is the same device but it is better if you add the prism to turn it into a Grism!
However, this can be done later.  Regards Andrew

Offline psjshep

  • Database dude... for the last breath of UKAI
  • Administrator
  • Galactic Poster
  • *****
  • Posts: 10209
  • My god! It's full of stars.... just often enough!
    • Some astro Pics
Re: Supernova 2012aw: Spectrum.
« Reply #10 on: 16:16:31, 26 March, 2012 »
 :thumbup:  understood.

Phil
--------------------------------------------------------------------------
Web Images

Offline Dave Grennan

  • Full Member
  • ***
  • Posts: 347
    • Irish Astrophotography
Re: Supernova 2012aw: Spectrum.
« Reply #11 on: 16:38:18, 26 March, 2012 »
Simon,

The SA I use is in fact the same one Bern sells.  The wedge prism I used is to help 'steer' the spectrum back to the centre of the optical train.  Its not essential it just helps to remove abberations.  For info the one I use is from edmund optical and its stock # is NT43-651.  You just pop this into the SA. align it so the spectrum of a light sourch is as close to the centre as possible and fix it with a bit of blu-tac.  Simples (chirp).

With a 4" scope you will be looking at classifying stars, even looking at some amazing stuff like radial velocity measurements in the faster moving stars. You can even classify planetary nebulae  My camera is an SBIG ST8 however any reasonable CCD will do, even a DSLR.

One thing you do need is the ability to track well.  If you can autoguide, fantastic.  With spectroscopy any thing more than minor trailing will smear out a lot of the detail.  However even for those with a dob, the SA can be used visually too.

Software:  I used RSpec
http://www.rspec-astro.com/
Its not the cheapest but it is very good and VERY easy to use.  Comes with lots of tutorial videos too.  The funny thing here is that one of the most comprehensive solutions VSpec by Valerie Desnoux
http://www.astrosurf.com/vdesnoux/
is free.  However the learning curve is a lot steeper again there are lots of tutorials.

Simon, go do it its fantastic fun.  One other resource well worth looking at is Richard Walkers spectral atlas.  Its free and is wonderful.  Very interesting even for those who dont do spectroscopy.

Also if anyone wants to learn a bit about the whole area in general, I can highly recommend
Astronomical Spectroscopy for Amateurs by our own Ken M.Harrison (merlin66 on these boards)
http://www.amazon.com/Astronomical-Spectroscopy-Amateurs-Practical-Astronomy/dp/1441972382

Delighted that this discussion has raised a bit of interest in the area.



Regards and Clear Skies,

Dave.
------------------------------
http://www.webtreatz.com
14" f/3.8 Custom Newtonian, WO GT81 Refractor, AP1200 Mount, Atik 460EX, SBIG ST8-XME, Lodestar and a whole pile of other stuff!

Offline bte999

  • Poster God
  • *****
  • Posts: 1037
    • Terry's Astrophotos
Re: Supernova 2012aw: Spectrum.
« Reply #12 on: 17:23:54, 26 March, 2012 »
Dave

Excellent bit of work (and good reference material as well).  It'll be interesting to see how the P-Cyg profile changes over time.

Mods - Sticky??

Terry
Terry Evans

TMB203 APO with SX Trius-694 on Paramount ME, Orion AG12 with SX-M25C

Offline koootzz

  • Administrator
  • Poster God
  • *****
  • Posts: 2956
Re: Supernova 2012aw: Spectrum.
« Reply #13 on: 18:56:56, 26 March, 2012 »
Very interesting stuff Dave, thanks for posting it.

Mods - Sticky??

Terry

Consider it done.
Leigh
vixen 60s, modded 1000D, modded 300D, DSI I, 10" dob (work in progress), some other bits and a stupendous talent for attracting cloud!

Offline andrew s

  • Full Member
  • ***
  • Posts: 373
Re: Supernova 2012aw: Spectrum.
« Reply #14 on: 19:27:55, 26 March, 2012 »
Other good free software for SA spectral reduction is ISIS available here http://www.astrosurf.com/buil/isis/isis_en.htm.

Andrew

 

ukbuysellRemote Imaging from AustraliaSharpSkyblank APTUKAI on Facebook
TinyPortal © 2005-2012