Call for monitoring of AG Dra by R. Galis & al.

Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Francois Teyssier » Fri Jul 20, 2018 10:50 am

Text about 2018 outburst of AG Dra
to be published in the next information letter
Of course we undergo the observations at low and higher résolution as requested by Jaroslav and Rudolf

François teyssier



The fourth hot outburst of AG Draconis during present active stage
Merc, J. & Gális, R.


AG Dra is a well-known symbiotic system manifesting a characteristic symbiotic activity with an alternation of active and quiescent stages. Active stages consist of the series of individual outbursts repeating at approximately one-year interval. AG Dra persisted in quiescence since the 2006-08 major outbursts. In May 2015, the brightness began to raise and the first, less prominent outburst (G0) during the new active stage of AG Dra was observed. It was followed by another three outbursts in April 2016 (G1), May 2017 (G2) and this year by the outburst in April 2018 (G3).
We closely monitor the activity of this symbiotic system using photometric observations and data obtained from the AAVSO International Database. Moreover, outbursts in 2016, 2017 and 2018 were extensively spectroscopically monitored by the ARAS observers. Thanks to the high number of involved observers, a unique photometric and spectroscopic material have been obtained. For the first time, we are able to track the evolution of AG Dra with almost one-day resolution.
So far the last observed outburst (G3) of AG Dra started in April 2018. The smooth increase of brightness was recognized at the beginning of the month (JD 2 458 211, B = 11.0 mag and V = 9.7 mag) and the onset of the new outburst was photometrically confirmed 11 days later (JD 2 458 222, B = 10.9 mag and V = 9.6 mag). The maximum was reached at JD 2 458 243 with a brightness of 10.2 and 9.5 mag in the B and V filters, respectively. According to the maximal brightness, it was a minor outburst of AG Dra. The increase of the He II/Hβ ratio (for the first time observed in the ARAS spectra from JD 2 458 223 and JD 2 458 227) as well as the increase of the equivalent widths of the prominent emission lines during the outburst suggest that this outburst was also of the hot type like the previous three outbursts in the present series. The brightness of AG Dra is gradually returning to the values typical for quiescence during July 2018.
Photometric, as well as spectroscopic behaviour, suggests that all four recent outbursts of AG Dra belong to the minor, hot type. Such evolution of the active stage is very unusual because minor pre-outburst at the beginning of the active stages were typically followed by major, cool outbursts. The next evolution of AG Dra is still an open question. Can we expect (finally) a major cool or (again) minor hot outburst? Another possibility is, that the symbiotic system will return to quiescence. According to our statistical analysis of photometric observations, we determined that the time interval between outbursts of AG Dra vary from 300 to 400d (without an apparent long-term trend), with a median around 360 d. If there will be an outburst during the spring of 2019, we can expect it in the interval from JD 2 458 581 (April 7, 2019) to JD 2 458 625 (May 21, 2019). By this time we suggest to continue in the spectroscopic monitoring of AG Dra with a lowered cadence (one higher resolution spectrum per 14 days). The observation material obtained between the outbursts and especially in quiescence is important for the study of the material distribution in the symbiotic nebula and of the processes responsible for the outburst activity.
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Francois Teyssier » Sun Aug 26, 2018 3:56 pm

After 2018 outburst, AG Dra monitoring

Equivalent width of the main lines
EW.PNG
EW.PNG (35.24 KiB) Viewed 676 times


Diagnostics ratios

Ha/Hb : near Balmer decrement for case B, rising
Temperature Hot Component (Iijima, 1981)

Diag.PNG
Diag.PNG (37.87 KiB) Viewed 676 times
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Francois Teyssier » Mon Mar 11, 2019 5:44 am

New season for AG Dra monitoring.
Waiting for a possible new outburst during spring, spectra are welcome in order to buid the baseline before outburst.
agdra_20190227_121_fteyssier.png

agdra_20190227_121_fteyssier_OVI.png
agdra_20190227_121_fteyssier_OVI.png (12.79 KiB) Viewed 282 times


François Teyssier
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Francois Teyssier » Thu Apr 11, 2019 4:04 am

The next outburst could

Form Rudolf Galis and Jaroslav Merc:

on the basis of our statistical analysis of photometric observations, we predict the time of next outburst of AG Dra in the interval from JD 2 458 581 (April 7, 2019) to JD 2 458 625 (May 21, 2019).

The program is still

1 weekly spectrum (low and high res) at least until the outburst in order to establish a base line

A spectrum (low and high res) a day during the outburst, because the behavior can be complex. see notably He II and OVI Raman.

agdra.png
agdra.png (21.04 KiB) Viewed 188 times


I've detected the strange emergence of a line at 5018 A (once deduced the systemic velocity) during the outbursts.

agdra1.png
agdra1.png (12.91 KiB) Viewed 188 times




François
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Francisco Campos » Sun Apr 14, 2019 5:45 pm

Hi,

here is my contribution from the last night, taken with the DADOS and the 1200 l/mm grating. I'm not sure if these spectra will be useful or not, because the resolution is about R=4000. Plus, I'm a bit worried about lambda calibration: it seems that the bands are a bit shifted from the expected position... or maybe it is a peculiarity of AG Dra? These spectra have already been corrected by heliocentric speed by ISIS...

Well... if resolution is not enough, I would come back to low-resolution...

Greetings,
Fran

agdra_ 20190413_978_FPC.png


agdra_ 20190413_912_FPC.png
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Francois Teyssier » Mon Apr 15, 2019 5:38 am

Hi Fran,
The systemic velocity is very high: -147.7 km/s (2.39 A at 4861 A)
The problem is the shape of the red edge of H beta and HeII (the "bump" is an artifact)

See e.g. Peter's spectra (R = 2500) in the database. http://www.astrosurf.com/aras/Aras_DataBase/Symbiotics/AGDra.htm

or at R = 11000

agdra_20190412_034_fteyssier.png
agdra_20190412_034_fteyssier.png (14.1 KiB) Viewed 141 times

(match well!)

At date, no sign of outburst

Let's go on. Excellent coverage for the baseline

François
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Olivier GARDE » Sat Apr 20, 2019 7:34 am

Last state of Ag Dra, a spectrum taken 2 days ago compare with my last observation the 28th March.

Image

Image
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby umberto sollecchia » Sat Apr 20, 2019 9:30 pm

Ma contribution, observation du 19.04.2019.
Umberto

agdra_20190419_799_U. Sollecchia.png
agdra_20190419_799_U. Sollecchia.png (26.8 KiB) Viewed 68 times
Last edited by umberto sollecchia on Sun Apr 21, 2019 2:18 pm, edited 1 time in total.
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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Paolo Berardi » Sun Apr 21, 2019 9:26 am

Hi all,

He II 4686 H-beta region with Lhires III and 1200 l/mm grating, 19/04/2019.

Image

The He II 4686 / H-beta EWs ratio is about 0.94. K giant absorption lines are clearly visible in the continuum.

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Re: Call for monitoring of AG Dra by R. Galis & al.

Postby Christophe Boussin » Mon Apr 22, 2019 2:58 pm

Hello all,

Here is my last contribution to the AG Dra monitoring.
I obtained the following spectrum the 21th of April at 00 h 05 TU with my Alpy 600 (resolution of 503, JJ = 2458594.5039) and an acquisition time of 50 min :

_agdra_20190421_004_Christophe Boussin_3700_7570.png
AG Dra on April 21th, 2019
_agdra_20190421_004_Christophe Boussin_3700_7570.png (72.59 KiB) Viewed 21 times


The comparison of my spectra (renormalized around their continuum) between 28 March and 21 April (with, as an indication, identification of some lines from PlotSpectra) :

agdra_20190328 et 20190411_21_(normcont)_Christophe Boussin.png
AG Dra on March 28th and April 11th, 21th 2019


The relative intensities of Balmer lines and HeII line at 4686A are decreasing but that of the Raman OVI line at 6830A remains constant :

agdra_Halpha(normcont)_Christophe Boussin.png
AG Dra (Halpha)
agdra_Halpha(normcont)_Christophe Boussin.png (22.39 KiB) Viewed 21 times


agdra_Hbeta(normcont)_Christophe Boussin.png
AG Dra (Hbeta)
agdra_Hbeta(normcont)_Christophe Boussin.png (22.88 KiB) Viewed 21 times


agdra_HeII4686(normcont)_Christophe Boussin.png
AG Dra (HeII 4686A)
agdra_HeII4686(normcont)_Christophe Boussin.png (21.84 KiB) Viewed 21 times


agdra_ramanOVI(normcont)_Christophe Boussin.png
AG Dra (Raman OVI 6830A)
agdra_ramanOVI(normcont)_Christophe Boussin.png (23.34 KiB) Viewed 21 times



Clear skies,

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan) @ ARAS database
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