PU Vul - fast Halpha evolution ?

[Christian Buil]

Last year (2013) Halpha intensity in PU Vul, a symbiotic star, was impressive (300 to 500 the continuum) - see
http://www.astrosurf.com/aras/Aras_Data ... /PUVul.htm.

Presently the intensity seem nearly - see this spectrum taken with VHIRES spectrograph (cloudy night and short exposure):



Confirmation and survey of the event is necessary (easy target for Alpy/LISA class setup).

Christian

[Paolo Berardi]

Hello Christian, currently I'm on PU Vul. In the first 960s frame with Lhires III 1200, h-alpha profile is close to saturation (60K ADU, I had to lower exposure time) while continuum is very faint.

This is a screenshot that include a raw profile (one row analysis).



I'll post the final spectrum when ready.

Paolo

[Paolo Berardi]

I had to stop for the clouds. Follows the final profile, 5 x 720 sec, scaled to 6615-6620 interval (perhaps there is some h-alpha line signal):



Paolo

[Christian Buil]

Many thanks Paolo for this observation (send this interesting result to François). Clearly, my target observed the 3/08 is not PU Vul ! A field star ?
I re-observe with VHIRES next night if weather is favorable...

Christian

[Robin Leadbeater]

I wonder what it is then? It looks like something interesting with off centre absorption in a weak emission. It might be a lucky discovery if you can find it again

Cheers
Robin

[Christian Buil]

Not evident. I have not field card during pointing during OHP "spectrum-party" ! have find the field by using only my memory (the origin of the problem, I think).

Christian

[Paolo Berardi]

A faint and very narrow line profile, perhaps only VHIRES is able to resolve it! Also PU Vul emission lines are really narrow (but stronger), for me it is a new type of spectroscopic target, very interesting! I sent the profile to François.

Paolo

[Hubert Boussier]

Bonjour,

J'ai profité d'une nuit claire et calme pour aller voir cette étoile. Elle n'est pas facile à trouver car assez faible, heureusement avec l'aide de Carte du Ciel et du chercheur électronique, j'ai pu l'identifier, après pas mal d'hésitations quand même.
Une fois le premier spectre affiché, plus de doute, l'émission Halpha est vraiment importante.


http://www.astrosurf.com/astrild/Pu_Vul.jpg

Avec plus de details


http://www.astrosurf.com/astrild/Pu_Vul_details.jpg

[Francois Teyssier]

Christian and all,
PU Vul is a symbiotic nova, recovering from its ourburt of 1979 (very slow nova)
The spectrum is nebular, very strong emission lines, weak continuum
It's very unlikely that H alpha shows such a variation in very short time-scale.

Selected publications :

Analysis of the nova outburst
http://adsabs.harvard.edu/abs/2012ApJ...750....5K
with interesting result about Diameter (red triangles) and Temperature (blue dots)

PUVul.PNG (22.25 KiB) Viewed 9391 times

High resolution lines
Nebular spectrum
http://adsabs.harvard.edu/abs/2007JKAS...40...39Y

Eclipsing symbiotic nova
http://adsabs.harvard.edu/abs/1996A%26A...307..470N

Ha profile at different dates (always strong)

PUVul_Ha.PNG (30.32 KiB) Viewed 9391 times

Amitiés,

François

[Christian Buil]

Merci pour tous vos spectres, Paolo, Hubert (excellents) !!!
Thanks for your excellent spectra

Cette affaire aura le mérite de faire découvrir cette étoile. Tu a raison François,
c'est du quasi pur nébulaire (je n'avais pas le spectre sur le terrain de l'OHP lorsque
j'ai pris la décision de la faire - c'est clair que c'est stable dans le temps a priori).

Pour me venger, je l'ai faite cette nuit avec VHIRES-MO.

Halpha est bien résolu, mais en contre-partie, la "faible" raie à 6586 A sort assez difficilement
du bruit alors qu'elle est facile sur les spectres de Paolo et de Hubert. On ne peut pas tout
avoir, c'est un vrai choix entre l'un et l'autre (résolution radiométrique vs résolution spectrale),
tous vraiment valables.

Halpha is easy to resolve (note présence if telluric lines in the shape).
Comparaison of SNR for the "faint" line at 6586 A is spectacular with Paolo and Hubert spectra.
I my spectrum the choice is very high spectral resolution (the difference between radiometric vs and spectral
resolution is well illustrated).

Also more lines visible in my spectrum (note presence of Fe VII).


Note redshift between atmospheric airglow [OIII] measured at 6300.306 A (compare to laboratory value of 6300.304 A -> give the precision of VHIRES for RV measure). The mean [OIII] measured on PU Vul (complex structure) is 6301.04 A (giving a possible RV for the star of +35 km/s - TBC).

Un large panorama de du statut de cette étoile avec tous nos spectres. Super !

Christian