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Alert Notice 724: VY Aqr observing campaign

November 9, 2020

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Campaigns and Observation Reports: https://www.aavso.org/vy-aqr-campaign
- Cataclysmic Variables: https://www.aavso.org/vy-aqr-outburst
- Spectroscopy: https://www.aavso.org/vy-aqr-campain
- Time-Sensitive Alerts: https://www.aavso.org/comment/74849
Please subscribe to these threads if you are participating in the campaign so you can be updated by the astronomers and by HQ. Join in the discussion or ask questions there!

Prof. Gregory Sivakoff (University of Alberta) provides the following material:

"Patrick Schmeer has identified that VY Aqr, an accreting white dwarf (aka cataclysmic variable) has gone into an outburst that looks to be a superoutburst (https://www.aavso.org/vy-aqr-outburst). VY Aqr is brighter than 10th magnitude right now (https://bit.ly/VYAqr_AAVSO). Despite being a relatively nearby cataclysmic variable that undergoes dwarf nova outbursts, VY Aqr is relatively understudied. Astronomers, both professional and amateur, now have the opportunity to study this superoutbursting WD in detail. Professors Gregory Sivakoff (University of Alberta) and Christian Knigge (University of Southampton) join Patrick Schmeer in requesting an AAVSO campaign on this object.

"We will be observing across the electromagnetic spectrum. We will use arrays of radio telescopes in South Africa, MeerKat, to study the relativistic jets that we suspect this source will launch. Using the Neil Gehrels Swift X-ray Observatory, we will study the X-rays that come from the inner accretion disk feeding the white dwarf. We will also use Swift to capture ultraviolet light (dominated by the mid accretion disk) and optical light (dominating the outer accretion disk; U / B / V filters). But we will only get MeerKAT and Swift data about once per day.

"This white dwarf has a companion that orbits it every 0.06309 d  (90.85 min) that supplies the material the white dwarf accretes. So changes to the source emission may happen on more rapid timescale than daily observations. AAVSO observers can play a major role in this campaign. To first order, a superoutburst will likely last around two weeks. Towards the end of the outburst, the source will decay towards its quiescent emission (mostly from the companion star) of 17th mag Visual. So we expect around 7 mags of changing optical emission over the outburst, with the AAVSO observers playing critical roles.

"We have six priorities for AAVSO observers. Please pick one given your capacity and interest.

    Capture B V timeseries data at as rapidly as possible a cadence given the magnitude of the source when you observe. Please observe B V B V B V ....
    Capture V timeseries data at as rapidly as possible a cadence given the magnitude of the source when you observe.
    Capture Visual (Vis or CV) timeseries data at as rapidly as a possible cadence given the magnitude of the source when you observe.
    Capture U B V timeseries data at as rapidly as possible a cadence given the magnitude of the source when you observe. Please observe U B V U B V U B V ....
    Capture spectra across as much of the optical range as possible (6563 Angstrom and ~5000 Angstrom are the most critical) at least once per day. It is important to be sensitive to absorption lines that will be fainter than the continuum level in your spectra.
    Capture spectra across as much of the optical range as possible (6563 Angstrom and ~5000 Angstrom are the most critical) as rapidly as your instrument will allow. It is important to be sensitive to absorption lines that will be fainter than the continuum level in your spectra.

"Superoutbursts are relatively rare. As Patrick pointed out, "According to AAVSO data, a normal outburst was observed 2006 October 7–11, and a superoutburst 2008 July 1–16 (followed by a rebrightening July 21–23). An outburst of unclear nature was observed from 2015 March 28 to April 1 by Rod Stubbings and the All-Sky Automated Survey for Supernovae (ASAS-SN)."

"So please join us on this fun and scientifically interesting opportunity."

Recent observations submitted to the AAVSO International Database (selected from over 700 obs) include:
2020 Oct. 30.90000 UT, 17.174 CV (G. Poyner, Birmingham, UK);
Nov. 01.92000, 17.093 CV (Poyner);
02.89030, <13.3 (A. Glez-Herrera, Ferrol, Spain);
03.89440, <13.6 (E. Muyllaert, Oostende, Belgium);
04.80210, <13.8 (Muyllaert);
04.88890, <13.3(Glez-Herrera);
05.74, <13.0 (P. Schmeer,
06.742, 11.2 (Schmeer);
05.80210, <13.8 (Muyllaert);
05.83500, 16.862 CV (Poyner);
06.73960, 11.3 (Muyllaert, independent detection);
06.742, 11.2 (Schmeer, discovery observation);
06.77700, 11.4 (visual, Poyner, confirming observation);    
06.81875, 10.4 (J. Toone, Shrewsbury, UK, independent detection);
06.83260, 10.8 (Muyllaert);
06.95500, 10.692 CV (Poyner);
07.06686, 10.387 B +/-0.019 (E. Schwendeman, Fincastle, VA);
07.06804, 10.532 I +/-0.135 (Schwendman);
07.06914, 10.535 V +/-0.004 (Schwendman);
07.70970, 9.6 (W. Kriebel, Schierling/Walkenstetten, Germany);
07.79514, 9.9 (J. Ripero, Madrid, Spain);
07.79860, 9.6 (Muyllaert);
07.90056, 9.764 TG +/-0.009 (Williamson);
08.00848, 9.851 CV +/-0.005 (F.-J. Hambsch, Mol, Belgium);
08.05751, 9.799 I +/-0.123 (Schwendman);
08.06029, 9.796 V +/-0.016 (Schwendman);
08.06138, 9.696 B +/-0.006 (Schwendman);
08.06502, 9.599 CV +/-0.015 (Hambsch);
08.09192, 9.749 CV +/-0.039 (Hambsch);
08.11494, 9.762 CV +/-0.002 (J. Ulowetz, Nprthbrook, IL);
08.40287, 9.702 B +/-0.003 (G. Myers, Hillsborough, CA);
08.40336, 9.862 V +/-0.003 (Myers);
08.49310, 9.8 (A. Pearce, Nedlands, W. Australia);
08.79900, 10.423 CV (Poyner);
08.85417, 9.5 (K. Geary, Kilann, Ireland);
08.87500, 9.6 (M. Deconinck, Artignosc sur Verdon, France);
08.91446, 9.705 TG +/-0.021 (G. Williamson, UK);
08.94097, 10.2 (L. Shotter, Uniontown, PA);
08.99609, 9.948 V +/-0.005 (D. Starkey, Auburn, IN);
08.99757, 9.884 B +/-0.007 (Starkey);
09.01431, 9.847 B +/-0.005 (Hambsch);.
09.01545, 9.928 V +/-0.004 (Hambsch);
09.06806, 9.904 B +/-0.007 (Starkey);
09.06834, 9.977 V +/-0.005 (Starkey);
09.08203, 9.926 V +/-0.004 (Hambsch);
09.08233, 9.842 B +/-0.006 (Hambsch);
09.09793, 9.942 V +/-0.005 (Starkey);
09.09823, 9.885 B +/-0.008 (Starkey);
09.11648, 9.964 V +/-0.006 (Hambsch);
09.11678, 9.891 B +/-0.008 (Hambsch);
09.73264, 10.4 (Schmeer);

Coordinates (2000.0): R.A. 21 12 09.25   Dec. -08 49 36.8 (from VSX entry for VY Aqr)

Finder charts with comparison stars for VY Aqr may be created using the AAVSO
Variable Star Plotter (VSP)
.

Submit optical observations: Please submit photometry and visual observations
to the AAVSO International Database using the name VY AQR.

Submit spectroscopic observations: Please submit spectroscopic observations to
the AAVSO Spectroscopy Database (AVSpec).

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen using material
supplied by Prof. Gregory Sivakoff.

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