Skip to main content

Nova Delphini

Ken4optics's picture
Ken4optics
Offline
Joined: 2012-04-02

We are collecting a significant amount of amateur spectral data (see the ARAS website).

http://www.spectro-aras.com/forum/viewtopic.php?f=5&t=682

Anyone with a grating or spectroscope should be working on this object. A chance of a lifetime!

The P Cygni profiles of the Balmer lines are impressive.....

nova Delphini 2013
Robin Leadbeater's picture
Robin Leadbeater
Offline
Joined: 2012-10-08

Here is a summary of the current situation from Olivier Thizy re amateur spectroscopy and details of how to take useful spectra. Amateurs were very quick on this one and have already generated a lot of data during the rarely well covered early evolution period

Robin

 ----- Original Message -----

From: Olivier Thizy

To: spectro-l@yahoogroups.com

Cc: François Teyssier ; Liste Amateur_Spectroscopy ; astronomical_spectroscopy@yahoogroups.com ; Steve Shore ; RSpec_Real_Time_Spectroscopy@yahoogroups.com ; staranalyser@yahoogroups.com

Sent: Friday, August 16, 2013 11:03 AM

Subject: [spectro-l] Nova Del 2013

 

Hello all,

thank you to all observers that have taken spectra of this new nova. It was brighter last night compared to the first night - by about one magnitude. It is also well visible with binoculars.

All spectrographs can be used. Low resolution (LISA, Alpy 600 but also star analyser) are showing all the emission lines that are "poping" out the continuum in a "P Cygni" profile. This profile, with a strong emission associated with a blue absorption, is an indication of strong outflow winds. The distance between the absorption and the emission is directly linked to the expansion speed which is huge (around 900km/s?).

Higher resolution spectrographs (Lhires III, eShel) are showing high level of details. The nova is very bright and there is lot of flux even for those high resolution spectrograph. In general, whatever the resolving power you are using, be careful with the saturation! If you have to focus on a selected region,use the 4800-6000 range (Fe II, He I, Na I lines...).

As François mentionned, a good reference star (I'm personally using that one now) is hd196544 (iota Delphinus; SAO 106322). It is close to the nova and the spectrum is in MILES database, facilitating the data reduction. It is recommended to take the reference at close airmass of the nova. Personnally, I am doing 1h observing runs and take the reference star for each run.

In addition to this reference star which is used during data reduction to correct your continuum, you can also observe a spectrophotometric standard which would be used at a later stage to calibrate your continuum in absolute flux. The recommended one is BD+28d4211:
alpha(2000) = 21h 51m 11.07s , delta(2000) = +28d 51' 51.8''
V = 10.51, B-V = -0.34, Spectral type: Op
Just process BD+28d4211 the same way as you process the nova.

This is the first opportunity for all the amateur spectroscopists to take such spectra with a bright, well positionned (for nothern hemisphere) and fast changing nova. Reactivity was there (amateur prooved to be reactive!) and there is a growing observing community. Make sure to not miss this opportunity and add your name on the list! :-)

When observing, please post your result on ARAS forum - this motivates other observers I'm sure:
http://www.spectro-aras.com/forum/viewtopic.php?f=5&t=682

See in particular Steve Shore explanation of what we are currently "seeing" in those spectra:
http://www.spectro-aras.com/forum/viewtopic.php?f=5&t=682&start=20#p2626

Olivier Garde's animations of the Halpha, Hbeta and Hgamma profiles, just in few hours during the first night, are also to see:
http://www.spectro-aras.com/forum/viewtopic.php?f=5&t=682&start=10#p2620

Last but not least, François Teyssier is collecting amateur spectra. It is easy to publish them:
1/ reduce your data into BeSS file format
2/ name your file with: _novadel2013_yyyymmdd_hhh_Observer  
    novadel2013: name of the nova, fixed forthis object
    yyyy: year
    mm: month
    dd: day
    hhh: fraction of the day, beginning of the observation
    Observer: your pseudo/name
Exemple: _chcyg_20130802_886_toto.fit
3/ send you spectra to François Teyssier to be included in the ARAS database visible here:
http://www.astrosurf.com/aras/Aras_DataBase/Novae/Nova-Del-2013.htm

Hope to see you soon in the list of observers!

Cordialement,

	Olivier Thizy
Nova Del 2013 - AAVSO Alert Notice 489
weo's picture
weo
Offline
Joined: 2010-03-25

AAVSO Alert Notice 489 on Nova Del 2013 has been published.

Keep up the great spectroscopy!

Good observing  -  Elizabeth Waagen, AAVSO HQ

Delphini, not Delphinus
weo's picture
weo
Offline
Joined: 2010-03-25

In the email version of Alert Notice 489, I called the nova Nova Delphinus 2013 when of course I should have called it Nova Delphini 2013. Sincere apologies for the absentmindedness!

Good observing, Elizabeth

rapid evolution in spectrum
Robin Leadbeater's picture
Robin Leadbeater
Offline
Joined: 2012-10-08

The spectrum is evolving rapidly and Steven Shore (Universita da Pisa) has requested continued coverage, particularly if possible more coverage from time zones away from Europe.  Further details here, with a detailed explanation of the processes going on currently in this nova.

  http://tech.groups.yahoo.com/group/spectro-l/message/14643

Cheers

Robin

Photometry in Steve Shore note
Roger Pieri's picture
Roger Pieri
Offline
Joined: 2010-08-02

 

Hi Robin,

Steve recommends to make photometry at the highest possible cadence. Do you know what it means ? Days, hours, minutes... At minute level I don't see much variation, within a couple of mmag. Within couple of hours each night the curve was very smooth. By chance the sky was very stable here those past three nights ! If we observe at few seconds level the scintillation will make the accuracy very poor under usual condition, not very usable.  

Cheers,

Roger

photometry cadence
Robin Leadbeater's picture
Robin Leadbeater
Offline
Joined: 2012-10-08

Hi Roger. 

Not really sure of the cadence required for photometry but there are certainly changes in the spectrum over ~1 hour currently. I think he is mainly trying to get as near continuous 24/7 coverage as he can during  this period of rapid change. You could check with with Steven Shore directly. He has invited questions on   <shore at df dot unipi dot it>

I finally got a spectrum tonight in a few minutes gap in the clouds (The first since it appeared) so at least I can add my name to the list of observers :-)

Cheers

Robin

I'm waiting for the spectrum
FMT's picture
FMT
Offline
Joined: 2010-08-14

I'm waiting for the spectrum Robin !

Here's a spectrum for tonight at R = 1000

There's now 96 spectra in the data base, from R = 6000 to 15000

Best regards

 

François

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484