V1369 Cen

[Francois Teyssier]

Good
There's details in the lines
But seems to be some problems with the continuum

A spectrum from Steve Shore (comparison between Nova Del and Nova Cen)

NovaDelCen.PNG (41.09 KiB) Viewed 20372 times

Bonne continuation

François (waiting the fits )

[Ken Harrison]

Francois,
The fits are coming!
Hmmm
Some of the detail looks comparable...loss of detail/ resolution down around Hgamma - probably due to focus?
Re. the continuum - I see the rise in my spectrum above the Hb - camera response?

[Terry Bohlsen]

I'm back from holidays so could take a spectra of this nova last night with my LISA. I'm not too keen on 3am. It needs to be this late to have it high enough to image. It will be much easier in a few months.
I tried 2 different stars to use as the instrument response star. There are no Miles stars anywhere this far south so I'm stuck with Pickles spectra.
I tried HD118991 (q Cen) which is suppose to be a B8V+ star. The spectra of it clearly shows a companion star spectra so I'm not going to use it. The separation is ~5arcsec so I can not isolate it.
see

I then tried HD 118978 which is conveniently nearby and is B9III which is in the Pickles database. It gave me a clean instrument response file but I can not use it to flux calibrate.
I was able to take simultaneous B and V measurements with my other scope so used this data to flux calibrate.
The result is below. It is still very bright at V = 4.27 so I was restricted to 3 sec exposures to prevent saturation. I took 26 exposures and combined them in Isis. The result is below.

A comparison of flux calibrated spectra of V1369 and Nova Del. The V mag isn't exactly the same. It shows how much further evolved V1369 is at a similar magnitude compared to Nova Del. This nova is much brighter.
Terry

[Ken Harrison]

I managed to get a spectrum of the Hb region before the clouds moved in.
The Hb and Fe line profiles seem to be showing a "secondary" (P-Cygni?) dip.
Any comments??

novaCen_Hb_301213.png (42.25 KiB) Viewed 20359 times

[Terry Bohlsen]

Ken
My spectra from the previous day shows a similar structure. I note a big difference in the Hg region though comparing the 2 spectra.
Terry

[Francois Teyssier]

Nice spectrum Terry ! Happy to see you're come back home !
What a chance to observe two bright novae the same year.
Bonne continuation

Ken : this is the classical multi-absorption system, well discribed by the precurssors, as Mc Laughlin (1960) or Payne Gaspochkin (1959)

Premaximum spectrum : "broad, blue shifted- absorption lines, often with addition of P cygni profiles"

Principal spectrum, at visual maximum : stronger and more blue-shifted absorption lines. They often show multiple substructures and they evolve into emission lines

Diffuse enhanced spectrum : appears after the maximum light : similar to principal spectrum but about twice as broad and blue-shifted

François

[Robin Leadbeater]

Ken
My spectra from the previous day shows a similar structure. I note a big difference in the Hg region though comparing the 2 spectra.
Terry

Soft focus at the blue end in Ken's spectrum perhaps? The Achromatic doublet in my LHIRES for example would certainly struggle to keep things sharp from 5400 to 4000A. The optics in the ALPY (and LISA) are so much better in this respect.

Cheers
Robin

[Ken Harrison]

Sorry for the delay.
Here's a collection of the nova spectra from 31stDec, 4th and 5th Jan.
(Francois - I've sent you a fit file for evaluation - let me know)

nova Cen_Ha_311213.png (31.74 KiB) Viewed 20291 times

nova Cen_Ha_040114.png (32.27 KiB) Viewed 20291 times

nova Cen_Ha_050114.png (31.12 KiB) Viewed 20291 times

nova Cen_Hb_311213.png (35.08 KiB) Viewed 20291 times

nova Cen_Hb_040114.png (41.25 KiB) Viewed 20291 times

nova Cen_Hb_050114.png (40.95 KiB) Viewed 20291 times

nova_Na_311213.png (40.42 KiB) Viewed 20291 times

nova Cen_Na_050114.png (45.29 KiB) Viewed 20291 times

novaCen_Hb_3112to 050114.png (59.86 KiB) Viewed 20291 times

[Terry Bohlsen]

This is my effort from last night. V mag has dropped from 4.27 on 28/12/13 to 4.88 on 5/1/14
The new version of Isis makes flux conversion very simple. I get exactly the same result using the single step in Isis compared with doing the conversion manually.
Terry

[Robin Leadbeater]

Hi Ken,

The apparent large increase at all wavelengths with time you are seeing in the Hb region looks rather strange compared with Terry's results which show only a small change over the same period. Your results almost look as though they are scaled relative to each other. How are your results plotted? Are the different days plotted with an offset ? (are they relative flux, absolute flux, raw counts? instrument response corrected?)

This could be a good opportunity to verify if the new BASS software produces reliable quantitative results. It would be interesting to see yours and Terry's data processed with both ISIS and BASS

Cheers
Robin