PNV J20233073+2046041 mag 6.8

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

Re: PNV J20233073+2046041 mag 6.8

Postby Paolo Berardi » Thu Aug 15, 2013 9:57 am

Great job Olivier! Evolution in so little time...

AAVSO provide Visual mag 5.4!

Paolo
Paolo Berardi
 
Posts: 169
Joined: Thu Sep 29, 2011 10:51 pm

Re: PNV J20233073+2046041 mag 6.8

Postby Terry Bohlsen » Thu Aug 15, 2013 12:43 pm

Dear All
This is my effort from tonight with my LISA on a C11 scope.
It is low in the north for me. I started imageing when it was at a Airmass of 1.8 and finished at AM 1.6
I could only use 60 sec exposures to start with and had to reduce them to 45 sec when it rose higher as the Hb region stated to become saturated.
I made a total of 30 exposures of decreasing length. I used 29 Vul (A0V) as the calibration star as it was at a similar airmass and reasonably close.
Cheers

Terry

Image
Terry Bohlsen
Armidale NSW
Australia
Terry Bohlsen
 
Posts: 95
Joined: Thu Sep 29, 2011 7:40 am

Re: PNV J20233073+2046041 mag 6.8

Postby Olivier GARDE » Thu Aug 15, 2013 1:53 pm

Paolo Berardi wrote:Excellent spectra!

ATEL #5282 reports Nova Del 2013 is a classical nova in the early fireball stage:
http://www.astronomerstelegram.org/?read=5282

I report here a couple of documents for novae:

In appendix (Table A1) of paper "Origin of the ‘He/N’ and ‘Fe II’ Spectral Classes of Novae" (R. Williams) there is a finding list for optical emission lines
http://arxiv.org/pdf/1208.0380.pdf

A reference document by S. N. Shore, Spectroscopy of Novae – A User’s Manual
http://arxiv.org/pdf/1211.3176.pdf

Paolo


Hi Paolo,
Thanks for yours links, I will read this documents as soon as possible....
Olivier GARDE
 
Posts: 195
Joined: Thu Sep 29, 2011 6:35 am
Location: Rhône Alpes FRANCE

Re: PNV J20233073+2046041 mag 6.8

Postby James Edlin » Thu Aug 15, 2013 4:27 pm

Hi All, It turns out that the very thick haze I was imaging the nova through last night was infact dense smoke from local forest fires. The sun rose this am dark cherry red. So I suspect that the blue portion of my spectra may not have a good instrument response. I suspect that the smole filtered out a significant part of the blue. I will hope for more clear sky conditions soon. What are people using for their reference star??

Jim
James Edlin
 
Posts: 12
Joined: Mon Oct 10, 2011 3:22 am

Re: PNV J20233073+2046041 mag 6.8

Postby Francois Teyssier » Thu Aug 15, 2013 9:13 pm

Reference star :

HD 196724 = 29 Vul

AD 20 38 31.33888
DE +21 12 04.24

Une A0V de mag V = 4.8


Francois
Francois Teyssier
 
Posts: 473
Joined: Fri Sep 23, 2011 1:01 pm
Location: Rouen

Re: PNV J20233073+2046041 mag 6.8

Postby Francois Teyssier » Thu Aug 15, 2013 9:14 pm

Comments from Steve Shore :

Francois asked that I bore you all with some explanation of what's
happening in these data and perhaps to give you all some idea of what
the physical picture is. It's a pleasure, also because it's a chance
to say thank you to all of you for this amazing, invaluable effort.
Once the smoke clears (well, after possible dust formation?), we'll
have a chance to work through all of this for the eventual complete
analyses. You're all involved with that.

First, this is a stage not often accessed in the optical, even less in
the ultraviolet. In the first stage, after the explosion (that we
don't see), the ejected outer layer of the white dwarf expand
hypersonically and cool. Two things. First, this is a mixture of the
stuff that was accreted on the WD during the pre-nova stage, when it
sits inside an accretion disk from the companion and like a garbage
disposal just accumulates the stuff. Once a sufficient pileup occurs,
the compressed layer can initiate nuclear reactions and explode (well,
this is the surface, not the center, so there's nothing to constrain
the event). BUT there's a question even here. Theignition of the
nuclear fuel is like a flame, in fact physically it's very close, and
propagates like a flame through the envelope. This, in turn, provokes
a buoyant mixing (to avoid the word "boiling" but it's a similar thing)
that also dredges material from deeper layers. A major uncertainty, of
almost cosmological importance, is how much of that mixed matter is
blown off and whether the WD mass increases or decreases. But that's
for another time.

For this stage, the explosion throws the gas off like a shell but with
a catch, the velocity depends on radius because the range of velocities
is ballistic and within an interval from the escape velocity to
whatever can be reached by the energy of the explosion. So you will
see velocities up to thousands of km/s. On this, a word of caution.

I'll always, in any of these notes, emphasize that what you see is NOT
the whole story. The ejecta are not completely transparent at all
wavelengths and you see to different depths of this fog -- just like a
fog -- depending on whether you're in the lines, continuum, the optical
or UV or IR -- in other words, a radiographic image of a human is
similar. You see to the depth from which the light can escape to you,
the surface -- the "photosphere" to those who want to be technical --
is wavelength dependent.

The same with the velocities. You see different line profiles on, for
instance, each Balmer line. Since the sequence from H-alpha to beta
and so on. is also one of intrinsic opacity (strength) you see deeper
in H-gamma than H-alpha and the line is formed mainly ("weighted
toward") the inner ejecta. So the combined line profiles, viewed in
velocity, are the probe -- tomorgraphy -- of the ejecta. With this you
can look for structure, dynamics, even variable abundances. The trick
is following the seqeunces and seeing how each part of the spectrum
develops. The Fe lines appear because the UV is opaque and the
absorption at high energy excited the optical (low energy) lines. The
same for the He and Balmer lines. In all cases, the classes (Fe, He/N)
are not anything but descritpicve of this stage.

The spectra you all got last night were from the fireball, the initial
stage of the expansion that is hard to catch. Now you'll see the next
pass, as the ejecta start to recombine and turn into a dense "fog".
Then, as they thin out (weeks from now, likely) the emission will
appear again but in the first stage the lines pass from ionized and He
and H to those of more easily ionzed heavy metals that would have been
too ionized to observe in the fireball.

I hope tis helps. It's just the star, if there's anything anyone would
like to see or if anyone has questions or comments, youknow I'm always
online (shore@df.unipi.it) even at the risk of filling all of our
mailboxes.

steve
Francois Teyssier
 
Posts: 473
Joined: Fri Sep 23, 2011 1:01 pm
Location: Rouen

Re: PNV J20233073+2046041 mag 6.8

Postby Francois Teyssier » Thu Aug 15, 2013 9:16 pm

Pros observations are scheduled
Chandra gave no result in gamma rays (this is normal) - Waiting ...
X and UV observations (SWIFT) are scheluded

François
Francois Teyssier
 
Posts: 473
Joined: Fri Sep 23, 2011 1:01 pm
Location: Rouen

Re: PNV J20233073+2046041 mag 6.8

Postby Olivier Thizy » Thu Aug 15, 2013 9:17 pm

Hello,


second night on the new nova Del 2013.

Equipment: EQ6 mount + Televue 85mm
Spectrograph: Alpy 600, 23µm slit, Ar-Ne calibration module
CCD: Atik 460EX (-10°C)

web_IMG_7174 Olivier et Alpy behind.jpg
web_IMG_7174 Olivier et Alpy behind.jpg (123.16 KiB) Viewed 1296 times



Reduced spectrum of 1h exposure (12*5min):

_novadel2013_20130815_865_OThizy.jpg
_novadel2013_20130815_865_OThizy.jpg (54.18 KiB) Viewed 1280 times



Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/
Olivier Thizy
 
Posts: 157
Joined: Sat Sep 24, 2011 10:52 am

Re: PNV J20233073+2046041 mag 6.8

Postby Francois Teyssier » Thu Aug 15, 2013 9:38 pm

Elle est magnifique.
On voit encore les absorptions du spectre pre maximum
Les profils P cygni sont intenses.

_novadel2013_20130815_879_fteyssier.png
_novadel2013_20130815_879_fteyssier.png (6.12 KiB) Viewed 1289 times


François
Francois Teyssier
 
Posts: 473
Joined: Fri Sep 23, 2011 1:01 pm
Location: Rouen

Re: PNV J20233073+2046041 mag 6.8

Postby Olivier GARDE » Thu Aug 15, 2013 11:48 pm

From the first spectra taken yesterday and the last, one day after, here's the evolution of H Alpha.

Image
Olivier GARDE
 
Posts: 195
Joined: Thu Sep 29, 2011 6:35 am
Location: Rhône Alpes FRANCE

PreviousNext

Return to Outbursts and alerts

Who is online

Users browsing this forum: No registered users and 2 guests

x