New transcient, perhaps a nova

Information about outbursts of eruptive stars, Be activity, ...

Re: New transcient, perhaps a nova

Postby Paolo Berardi » Wed Jul 05, 2017 5:06 pm

Great spectra Woody, Umberto! I don't know about the small continuum discrepancy between your profiles. I hope other people observed the nova (in a full spectral range), so we can check.

Nice evolution in a few days. Brightness increased to mag V 11.06. Many Fe II lines have arisen in the profile around H-beta emission line:

Image

Source of line ident: Williams, 2012 (the link provided above by François and Woody)

H-beta velocity is around -400 Km/s, Fe II multiplet 42 velocity is around -380 Km/s (both measured on P-Cygni minimum).

Paolo
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Re: New transcient, perhaps a nova

Postby Forrest Sims » Wed Jul 05, 2017 5:41 pm

Ciao,

Umberto and Paulo, Many thanks. I hope I have not hijacked this thread with my questions on this curve. I will try a different Reference Star. Umberto I do see that the star you used HD179761 is in the MILES database. I do not see it in the search list for this transient target when I use either the MILES_Search_V1 tool nor the ReferenceStarFinder Excel tools. However as you suggest I will use a different star. Here is my response corrected profile curve for HD207673 (A2Ib) and also plotted the MILES profile curve from the ISIS database. They appear to be a pretty good match from 4200Å to 5900Å.

Paulo, I currently do not have a second monochrome camera to use with my Astrodon Johnson/Cousins Photometric V Band filter to obtain the V magnitude of our target. When I do get one I can use a second OTA for measuring the V magnitude. Until then, how much error do you think I would have if I used your recent measured V magnitude with my spectrum data. Is this what Umberto is using? Would this be useful with my spectrum data or way too inaccurate?

I can see in the two curves I uploaded that I need to learn more about how to slice out parts of my curve to the right of 6800Å with the ISIS Continuum tool to get a better match with the MILES curve.

Saluti -
Woody
Attachments
HD207673 response corrrected plus MILES curve.png
HD207673 response corrrected plus MILES curve.png (45.18 KiB) Viewed 3473 times
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Updated information: ATeL #10558

Postby Paul Luckas » Thu Jul 06, 2017 3:52 am

Title: Continuing spectroscopic monitoring of Nova Sct 2017 = ASASSN-17hx
Author: Paolo Berardi, Woody Sims, and Umberto Sollecchia (ARAS Group)
Password Certification: S. N. Shore

http://www.astronomerstelegram.org/?read=10558
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Re: New transcient, perhaps a nova

Postby Olivier GARDE » Thu Jul 06, 2017 7:57 am

Congratulation for this Atel !!!
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
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Re: New transcient, perhaps a nova

Postby Paolo Berardi » Thu Jul 06, 2017 10:50 am

Thank you Paul, Olivier. Of course, many thanks go to Steve and François (who can handle the pro-am link even while on holiday!).

Woody, your fit is certainly valid (just a small excess around 4000A). The starlight from HD207673 seems to me very reddened for an A2 class star (see the flattened continuum and the Na D deep absorption), although the Miles catalog report E(B-V)=0. Anyway, if the library profile is the observed spectrum (like any other one in the ISIS library), your calibration is correct. You should have confirmation if you calibrate the nova spectrum with another Miles star. If not, we can try to observe and calibrate HD207673 with a response curve calculated with another Miles star, then compare it with the library profile.

The V magnitude during my observation (from ~ 21:00 to 22:30 UT July 4) was stable enough. See:

Image

Unfortunately yesterday I didn't observe the nova and I don't know the brightness trend. AAVSO reports a few measures and I don't understand if the nova lightcurve was on an horizontal segment around July 4 (so you could use it without making large errors). Umberto observed almost at the same time (we coordinate by phone) while your observation is ~ 14 hours early. I don't know...

I hope to observe the nova again if the brightness holds.

Paolo
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Re: New transcient, perhaps a nova

Postby Francois Teyssier » Thu Jul 06, 2017 12:20 pm

Congratulations to Paolo, Umberto and Woody!
All the best,
François
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Re: New transcient, perhaps a nova

Postby Christian Buil » Thu Jul 06, 2017 5:32 pm

Only for the fun i.e. poor science (et aussi à cause d'un vent très fort, comme toujours à Toulouse,
empêchant d'observer autrement !), with a D = 65 mm refractor F = 420 mm (TS Optic)
(15 microns slit for the Alpy600)

Image

12x300 s + 10x600 s exposure (bin 2x2) + severe wind.

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Re: New transcient, perhaps a nova

Postby Forrest Sims » Thu Jul 06, 2017 9:38 pm

Thank you Paolo and Paul. And as Paulo said many thanks to François for the enormous work he does and Steve Shore for so graciously including my data along with that of Paolo and Umberto.

Paolo, I have read you comments and spent some time thinking on your suggestions which sends me off to read and slowly increase my understanding:) Unfortunately our weather forecast is for cloudy nights for the next week. So it gives me time to look at old data and study. I pulled up my Reference star HD204754 data that I used for the assassin-17hx target on 30 June. Using Tim Lester's PlotSpectra I have two curves. The response corrected HD204754 and the MILES fits file in the ISIS database. I see the similar (small excess around 4000Å) and also the absorption lines for Na D at about 5890Å and 5895Å differences between my response corrected curve and the MILES curve. See attached plot.

The excess around 4000Å is a bit puzzling. I will have to keep and eye on this to see if I can determine the cause.

Saluti -
Woody
Attachments
hd204754_20170630_255_Woody Sims IR corrected plus MILES Curve.png
hd204754_20170630_255_Woody Sims IR corrected plus MILES Curve.png (32.84 KiB) Viewed 3426 times
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Re: New transcient, perhaps a nova

Postby Terry Bohlsen » Fri Jul 07, 2017 10:42 am

I took my first spectrum of this nova last night as well as the one in Centaurus. Below is the comparison. Very similar levels at the same time.
Terry
Novascutumand cen.png
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Australia
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Re: New transcient, perhaps a nova

Postby Christian Buil » Fri Jul 07, 2017 4:57 pm

Observation 6.890/07/2017 by using now a FSQ106ED refractor (D=106 mm) + Alpy 600 (15 microns slit and binning 1x1 Atik460EX) :

Image

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