V442 And Be star in outburst

[Olivier Thizy]

Hello,


I took a spectrum of V442 And on the morning of august 22nd. The first image clearly showed an emission. Proper data reduction of the serie compared to Valérie Desnoux spectrum (dated july 31st) show the outburst:

Valérie's spectrum seem to show some faint emission. But evolution is very quick as Christian Buil spectrum taken on the evening of august 22nd shows:

V442_And_CB.png (24.15 KiB) Viewed 7996 times

A look at previous years show that V442 And is a very active Be star with period of quiet and period of outbursts. The required observation period in ARASBeAm is set at 30 days so a continuous observation of this target seems a good idea. There are 97 spectra of this star in ARASBeAm/BeSS database. Here is a graph with a spectrum taken about every year, showing activity in 2007, 2010, 2013, 2014, 2016 and now 2017:

Definitively a star to monitor closely...


Last but not least, I am running all my observatory (Losmandy titan mount, robofocus, dome control, cameras, spectrograph lamps...) with PRISM v10 software. Here is a screenshot showing the echelle spectrum (for those who know how to read it, the emission is actually slightly visible on the image), the guiding image, an intensity monitor, a guiding tracking monitor, camera controls, telescope (Gemini.Net) control, and a skymap showing the telescope position. I find very useful to run everything from a single all-in-one software as I do not have to learn multiple software this way and it's all connected or remote (and hopefully soon) automated observations:

And an overexposed (10 sec) guiding image showing V442 And on the fiber tip (not visible due to too long exposure):

ATIK HS V442 And.jpg (146.88 KiB) Viewed 7996 times

Cordialement,
Olivier

[Christian Buil]

V442 And is a well active star - day to day evolution presently...

Another look of my spectrum taken last night
(C9.25 telescope + eShel + ...
Atik460Ex -> a tip, I recommend to use bin 1x1 mode for reduce sampling noise (pseudo-noise) and finally,
for ultimate detectivity - bin 2x2 is a false friend when using eShel).



Telluric lines are removed.

For comparison, same setup, same scale graph as V442 And and taken the same night, the Be star QR Vul:



and the Be KY And :



J'utilise moi aussi à présent Prism pour l'acquisition et le guidage, mais fichtre, je n'arrive toujours pas à organiser et garder
fixe la taille et la position les fenêtres... je rêve d'avoir l'ordre qui reigne sur ton écran Olivier !



Au passage noter comment on voit l'étoile en reflexion sur la face d'entrée de la fibre (0,05% du flux réfléchit). Quant c'est comme cela veux dire que le seeing est bon, ce qui est plutôt rare chez moi. En parallèle sur le télescope un objectif photo Nikon de 50 mm associé à une caméra ASI1600MM-COOL servant de chercheur, ici le champ de KY And :



Ca peut servir de moniteur à nuages, ici durant l'observation de QR Vul, un peu chaotique...



Christian

[Olivier Thizy]

Christian,


nice your screenshots! By the way, thanks for the PRISM improvements suggestions - I love not to clic on "no autocontrast" anymore!
Regarding the windows, yes the screen is full. There has been a small change and now the Dome/Telescope location and the RoboFocus (yes, I have added one recently, great to finetune the focus even during an exposure!) screen can be easily found using the small Windows preview:

Anyway, here is my spectrum from tonight (only one 20min exposure; I am taking spectra at the moment!) and the change in less than 48hr is impressive on this Be star:

Cordialement,
Olivier

[Olivier Thizy]

Hello,


The V peak is now higher than the R peak, change took place during the last 24hours:

I did three 1hr runs on V442 And tonight but no change is clearly visible:

Hum... interesting....


Cordialement,
Olivier

[Olivier Thizy]

Hello,


again, V/R has changed in less than 24h (here is just one 20min spectrum compared to 1h session last night):

I will try, if weather cooperate, to monitor through the night to see if I can detect any change during that time...


Cordialement,
Olivier

[Olivier Thizy]

Hello,


I have a good weather and I can continue my spectroscopy observations of V442 And...


Tonight the profile is closer to last night. Here are the changes for the last 4 nights:

Note that I also revised my article on Be stars:
https://observatoire-belle-etoile.blogs ... tatus.html

And I just wrote a short biography on V442 And (HD6226) with some interesting informations on positive correlation betwee, photometry and spectroscopy; but overall summary is that V442 And is a star that should be further studied:
https://observatoire-belle-etoile.blogs ... raphy.html


Cordialement,
Olivier

[Olivier Thizy]

Hello,


after a 6h monitoring on V442 And, I think I notice a small increase of the V peak on the first hour and a decrease of the R peak on the last two hours:

I do not think this is my imagination nor noise... or is it?


Cordialement,
Olivier

[Olivier Thizy]

Hello,


The nice thing about ARAS is that this is a network of observers and when weather is cloudy on one location, there is usually another location with clear sky. Thanks to Christian Buil that observed the bight after the outburst announcement and Joan Guarro Flo whic observed last night, we have data almost every 24h on V442 And. And spectra do show changes night after night - a very interesting target for the moment so do not hesitate to observe it (and upload spectra on BeSS).

Anyway, here is the evolution of V442 And for 8 consecutive nights after the outburst has been discovered:

V442 daily evolution aug21-aug28.JPG (70.44 KiB) Viewed 7790 times

Note that tonight emission is a double peak with the R peak higher than the V peak. Daily changes in the profile are really impressive. Hope data could be useful afterward to better understand the outburst mechanism?...

Cordialement,
Olivier

[Joan Guarro Flo]

Good Series, Olivier !!

This past night, here has been a cloud. Zero results ...

Joan.

[Olivier Thizy]

Hello,


here is tonight's spectrum compared to last night, again some change in the emission profile:

Here is the updated monitoring (one spectrum per night) showing a longer term evolution:

Unfortunatly weather forecast is bad for me for the next few days:

Capture Weather Revel 2.JPG (60.06 KiB) Viewed 7758 times

So I hope some of you can pick it up and observe V442 And every night (high resolution, R>10000 if possible; ideal would be as for all Be stars a SNR>100 on the continuum close to Halpha, personally with 1h exposure, I get around SNR=85 as measured by ISIS using FWHM menu and looking at SNR2 value)... it would be nice to get a good time coverage for the emission evolution and see in few weeks how it evolves, if there is any period (2.615d for exemple, which is the star rotation period), etc... Joan, hope you get good weather on your side!

If you observe, of course upload your spectra on BeSS database and please send me your FITS file so I can update the graph...


Cordialement,
Olivier