CVnet - Cataclysmic Variables Network

AAVSO Alert Notice 724: VY Aquarii campaign
9 November 2020

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Campaigns and Observation Reports:
- Cataclysmic Variables:
- Spectroscopy:
- Time-Sensitive Alerts:
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 ( VY Aqr is brighter than 10th magnitude right now ( 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,
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.

AAVSO Alert Notice 720: Photometry requested for SS Cygni
13 September 2020

Dr. Mariko Kimura (RIKEN, Japan) requests AAVSO assistance in obtaining V and Rc photometry of the cataclysmic variable SS Cyg in support of an orbital period study.

Dr. Kimura writes: "The X-ray flux of SS Cyg is now increasing and 10-times larger than usual.  This object is brightest at X-ray wavelengths in these 25 years.  The quiescent level of the optical luminosity is also rising.  I consider that this increase of the optical baseline may be caused by the X-ray irradiation of the outer accretion disk and/or the secondary star.  In this case, we could see the irradiation component of the secondary star becomes dominant in the orbital light curve.  I would like to confirm this hypothesis by intensive filtered optical photometry during the quiescent state.  

"I tried to derive the orbital profile from the data taken by the AAVSO observers during the recent 1 yr, but the data was not enough.  More observations are necessary and V-band or R-band photometry is preferable."

Multiple V and Rc CCD and PEP observations per night are requested beginning now. Visual observations (not more than one per night for this campaign) are welcome. The campaign will continue until the SS Cyg X-ray flux has returned to usual levels. The end of the campaign will be announced in the AAVSO forum threads given above; please be sure to subscribe to be kept informed.

As Dr. Kimura mentioned, SS Cyg has also been behaving atypically in the optical over the past several months. Observations in the AAVSO International Database indicate that SS Cyg was at visual magnitude 10.8 on 2020 Sep. 13.28120 UT (G. Sarty, Saskatoon, SK, Canada). SS Cyg has a V range of 7.7–12.4.

Coordinates (J2000): R.A. 21 42 42.79  Dec. +43 35 09.9 (from VSX entry for SS Cyg)

Charts with comparison stars for SS Cyg may be created using the AAVSO Variable Star Plotter (VSP).

Please report all observations to the AAVSO International Database using the name SS CYG.

This AAVSO Alert Notice was prepared by Elizabeth O. Waagen.

It’s all about the  standstills, those episodes where the star gets stuck at a mid-point between maximum and minimum. If it doesn’t exhibit standstills it isn’t a Z Cam star.

Data from Catalina Real Time Survey 

Drake et al. 2009, ApJ, 696, 87

Northern CVs brighter than 17th magnitude here.

Southern CV's brighter than 17th magnitude here.


Last updated 21:50 on 25 November 2020

(All objects mentioned in this section are in the International Variable Star Index; additionally, VSX links have been given for selected cataclysmic variables) 

New outbursts and unusual activity reported in the last 72 hours


V452 Cas

MASTER OT J203937.54+213904.7

AR And
U Gem
KZ Gem:
CW Mon
BX Pup
NSV 14581

Current superoutbursts (since ...)
MR UMa (20201113)
IX Dra (20201109, UGER = ER UMa subtype)
VY Aqr # (20201106, first rec. outburst since 2015 Mar.–Apr., time-resolved photometry required)
VZ Pyx (20201104, UGSU)
NSV 35 (20201101, UGSU)
KP Cas (20201031, UGSU)
ASASSN-15pk (20201031, UGSU, superhump period 0.0814(13) d)
1RXS J012750.5+380830 # (20201024, UGSU, time-resolved photometry is required)
Mis V1448 # (20201016, at least two rebrightenings)
AY Lac # (20201008, UGWZ, time-resolved photometry is urgently required)
KK Cnc # (20201003, UGWZ)

Z Cam-type dwarf novae at standstill
HL CMa (since 20191106 or earlier)
Z Cam (since 20181012)
V2837 Ori (20191106–20191123; IW And star, eclipsing, Porb= 0.2761069 d)
CK Eri (20190925–20191029, outburst 20191030; IW And star?)
RX And (20190614–20190714)
V507 Cyg (20190403–20190706, IW And star)
AT Cnc (20190212 – 20190603)
1RXS J062954.6-033520 (20190228–20190316)
UY Pup (20181129–20181217)

# indicates a noteworthy or unusual outburst
:  indicates confirmation required
'Activity at a Glance' is gleaned from observations reported to AAVSO MyNewsFlash, BAAVSS-Alert, CVnet-Outburst, VSObs-share and VSNET-outburst. We sincerely thank all the observers who contribute timely observations and reports of activity to these email lists.


16 October 2020

For new papers on CV's see astro-ph

Joseph Patterson (1), Jonathan Kemp (2), Berto Monard (3), Gordon Myers (3), Enrique de Miguel (4), Franz-Josef Hambsch (3), Paul Warhurst (5), Robert Rea (3), Shawn Dvorak (3), Kenneth Menzies (3), Tonny Vanmunster (3), George Roberts (3), Tut Campbell (3), Donn Starkey (3), Joseph Ulowetz (3), John Rock (3), Jim Seargeant (3), James Boardman (3), Damien Lemay (3), David Cejudo (3) ((1) Columbia Univ., (2) Middlebury Coll., (3) Center for Backyard Astrophysics, (4) Univ. de Huelva, (5) Univ. of Auckland)

E.J. Harvey, M.P. Redman, P. Boumis, S. Akras, K. Fitzgerald, S. Dulaimi, S.C. Williams, M.J. Darnley, M.C. Lam, 1 M. Kopsacheilli, S. Derlopa

Mariko Kimura, Keisuke Isogai, Taichi Kato, Naoto Kojiguchi, Yasuyuki Wakamatsu, Ryuhei Ohnishi, Yuki Sugiura, Hanami Matsumoto, Sho Sumiya, Daiki Ito, Kengo Nikai, Katsura Matsumoto, Sergey Yu. Shugarov, Natalia Kathysheva, Hiroshi Itoh, Pavol A. Dubovsky, Igor Kudzej, Hiroshi Akitaya, Kohei Oide, Takahiro Kanai, Chihiro Ishioka, Yumiko Oasa, Tonny Vanmunster, Arto Oksanen, Tamás Tordai, Katsuhiro L. Murata, Kazuki Shiraishi, Ryo Adachi, Motoki Oeda, Yutaro Tachibana, Seiichiro Kiyota, Elena P. Pavlenko, Kirill Antonyuk, Oksana Antonyuk, Nikolai Pit, Aleksei Sosnovskij, Julia Babina, Alex Baklanov, Koji S. Kawabata, Miho Kawabata, Tatsuya Nakaoka, Masayuki Yamanaka, Kiyoshi Kasai, Ian Miller, Stephen M. Brincat, Wei Liu, Mahito Sasada, Daisaku Nogami

Han Zhongtao, Boonrucksar Soonthornthum, Qian Shengbang, Fang Xiaohui, Wang Qishan, Zhu Liying, Dong Aijun, Zhi Qijun

Christopher Lloyd, Lewis M. Cook, Seiichiro Kiyota, Hanjie Tan, Di Hu, Wei Shi, Mi Zhang, Shenwei Zhang, Xiaowei Zhang, Jingyuan Zhao, Guoyou Sun, Xing Gao, David Boyd

D. M. Hewitt, M. L. Pretorius, P. A. Woudt, E. Tremou, J. C. A. Miller-Jones, C. Knigge, N. Castro Segura, D. R. A. Williams, R. P. Fender, R. Armstrong, P. Groot, I. Heywood, A. Horesh, A. J. van der Horst, E. Koerding, V. A. McBride, K. P. Mooley, A. Rowlinson, B. Stappers, R.A.M.J. Wijers

John R. Thorstensen, Mokhine Motsoaledi, David A. H. Buckley, Patrick Woudt, Brian Warner

M. D. Stritzinger (Aarhus), F. Taddia (Aarhus), M. Fraser (Dublin), T. M. Tauris (Aarhus), C. Contreras, S Drybye, L. Galbany, S. Holmbo, N. Morrell, A. Pastorello, M. M. Phillips, G. Pignata, L. Tartaglia, N.B. Suntzeff, J. Anais, C. Ashall, E. Baron, C. R. Burns, P. Hoeflich, E. Y. Hsiao, E. Karamehmetoglu, T. J. Moriya, G. Bock, A. Campillay, S. Castellon, C. Inserra, C. Gonzalez, P. Marples, S. Parker, D. Reichart, S. Torres-Robledo, D. R. Young

O. Segura Montero, S.H. Ramirez, J. Echevarria

Susanne M Hoffmann, Nikolaus Vogt, Philipp Protte

Taichi Kato, Yasuyuki Wakamatsu, Naoto Kojiguchi, Mariko Kimura, Ryuhei Ohnishi, Keisuke Isogai, Keito Niijima, Tomohiro Yoshitake (Kyoto U), Yuki Sugiura, Sho Sumiya, Daiki Ito, Kengo Nikai, Hanami Matsumoto, Katsura Matsumoto, Tonny Vanmunster, Franz-Josef Hambsch, Hiroshi Itoh, Julia V. Babina, Oksana I. Antonyuk, Alex V. Baklanov, Elena P. Pavlenko, Berto Monard, Shawn Dvorak

Susanne M. Hoffmann

E.Pavlenko, K. Niijima, P. Mason, N.Wells, A. Sosnovskij, K. Antonyuk, A. Simon, N. Pit, C. Littlefield, H. Itoh, S. Kiyota, T.Tordai, P. Dubovsky, T.Vanmunster, G. Stone, T. Kato, A. Sergeev, V. Godunova, E. Lyumanov, O. Antonyuk, A. Baklanov, Ju. Babina, K. Isogai, Ya. Romanyuk, V.Troianskyi, V. Kashuba

J. Casares, T. Muñoz-Darias, D. Mata Sanchez, P.A. Charles, M.A.P. Torres, M. Armas Padilla, R.P. Fender, J. Garcia-Rojas

G. J. M. Luna (1,2), T. Nelson (3), K. Mukai (4,5), J. L. Sokoloski (6,7) ((1) CONICET-Universidad de Buenos Aires, Instituto de Astronomía y Física del Espacio (IAFE), (2) Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina, (3) Department of Physics and Astronomy, University of Pittsburgh, (4) CRESST and X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center, (5) Department of Physics, University of Maryland, Baltimore County, (6) Columbia Astrophysics Lab, Columbia University, (7) Large Synoptic Survey Telescope Corporation)

Bradley E. Schaefer, David Boyd, Geoffrey C. Clayton, Juhan Frank, Christopher Johnson, Jonathan Kemp, Ashley Pagnotta, Joseph O. Patterson, Miguel Rodriguez Marco, Limin Xiao