CVnet - Cataclysmic Variables Network

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.

AAVSO Alert Notice 714: 

TCP J21040470+4631129 to be observed with HST
6 August 2020

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Campaigns and Observation Reports:
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!

(Note: This campaign was originally scheduled for March and April but was postponed due to the outburst of the system in March 2020.)

Dr. Boris Gänsicke (University of Warwick) has requested AAVSO assistance in monitoring the WZ Sge-type dwarf nova TCP J21040470+4631129 (in Cygnus) in support of observations scheduled with the Hubble Space Telecope for sometime between 2020 September 8 and 20.

All dates in this Alert Notice will be refined when the exact date/time of the HST observations is released by STScI. It is extremely important for observers to subscribe to the forum threads given above for the campaign so as to be informed of the exact date and time of the HST observations. This Alert Notice will also be updated with the exact date and time.

AAVSO observations are essential to know the state of TCP J21040470+4631129 in order to ensure that the system is NOT in outburst when observed with HST. AAVSO observations made 24 hours before the HST observing time will be used to make a go/no-go decision; AAVSO data will be used in the analysis of the resulting HST data.

Nightly snapshots in V are requested beginning now and continuing through September 25 (date may change). Intensive monitoring is requested September 6 – 20 (dates will change). During the period of intensive observations, prompt submission of observations will be essential. The most critical need for a positive observation is the night that is 24 hours before the HST observations (to be announced). Visual observations are also welcome.

TCP J21040470+4631129 has a range in V of 8.4–18.1. Its last major outburst occurred in July 2019, when it reached magnitude 8.293 V, and was followed by several re-brightenings, the most recent of which occurred in March 2020. The most recent observation of TCP J21040470+4631129 in the AAVSO International Database shows it at magnitude 15.248 V +/-0.083 on 2020 Aug. 05.0108 UT (S. Dufoer, Brussels, Belgium).

Coordinates (J2000): R.A. 21 04 04.68  Dec. +46 31 14.5

Charts with comparison stars for TCP J21040470+4631129 may be created using the AAVSO Variable Star Plotter (VSP).

Please report all observations to the AAVSO International Database using the name TCP J21040470+4631129.

This Alert Notice was compiled by Elizabeth O. Waagen.

AAVSO Alert Notice 713: Unusual Nova in Aquila:
Nova Aquilae 2020 No. 2 
= PGIR20eig = AT 2020qpq 

Note: The table of Observations submitted to the AAVSO was replaced to correct errors in this table in the original version of the Alert Notice.  -  Elizabeth O. Waagen, 3 August 2020

3 August 2020

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Time Sensitive Alerts:
- Novae:

Please subscribe to these threads if you are observing this nova so you can be updated as to its behavior and any observing campaigns on it. Join in the discussion or ask questions there!

Event: Unusual Nova in Aquila: N Aql 2020 No. 2 = AT 2020qpq = PGIR20eig

Discovered by: Palomar Gattini-IR collaboration (PGIR)

Discovery magnitude: 13.35 J +- 0.22
Discovery date: 2020 July 13.26 UT

Coordinates (2000.0): R.A. 19 14 26.27   Decl. +14 44 40.1   (from VSX page for N Aql 2020 No. 2)

Spectra: A spectrum obtained by De et al. (ATel #13914) on 2020 August 2 UT using the SED Machine spectrograph on the Palomar 60-inch telescope shows the object to be a reddened classical nova.

Observing recommendations: This nova is unusual in that it has been brightening for 20+ days. It is faint but it may keep brightening for some time as a Type B or C nova (or something else) so starting coverage now could be really valuable. Please observe the nova as it evolves, with observations of all types (visual, CCD, DSLR, spectroscopy) and multiple bands as instrumentation permits.

Observations reported to the AAVSO:

Observations reported to the AAVSO (corrected from initial version):
2020 Jul. 11 UT, <13.7 J (Palomar-Gattini, via ATel #13914);
13.26, 13.35 J (Palomar-Gattini, discovery observation, via ATel #13914);
14.3359 17.488 g +/-0.098 (Zwicky Transient Factory (ZTF), from Lasair website);
18.3937 16.259 r +/-0.035 (ZTF);
21.3633 16.263 r +/-0.048 (ZTF);
24.3378 15.869 r +/-0.035 (ZTF);
26.3545 15.783 r +/-0.047 (ZTF);
27.2528 17.323 g +/-0.038 (ZTF);
27.3172 15.659 r +/-0.040 (ZTF);
31, 12.55 J +/- 0.11 (Palomar-Gattini), via ATel #13914);
31.2900 15.431 r +/-0.037 (ZTF);
31.2904 15.472 r +/-0.045 (ZTF);
Aug. 02.2509 16.976 g +/-0.041 (ZTF);
02.2746 15.172 r +/-0.027 (ZTF);

Corrected ZTF magnitudes are courtesy of S. Otero (AAVSO HQ), who also notes that the ZTF g and r magnitudes from August 2 may be used to derive a V magnitude = 15.9.

Charts: Charts with comparison stars for N Aql 2020 No. 2 may be created using the AAVSO Variable Star Plotter (VSP). Be sure to include spaces in the name as shown. There are magnitude ~12 and ~13 stars nearby to the East, so please be careful in identifying the nova, especially as it fades.

Submit observations: Please submit observations using the name N AQL 2020 NO. 2.
When a GCVS name is assigned to this nova, please use it when submitting observations.
 - Submit optical observations to the AAVSO International Database using WebObs (see below).
 - Submit spectra to the AAVSO Spectroscopy Database (AVSpec).

a. Discovery announced by De et al. in ATel #13914 (2020).

b. De at al. report no source was found at their location on archival 2MASS images.

c. Position end figures
- De et al. (2020 Jul. 13 UT): 26.3s, 40.0"

Congratulations to the Palomar Gattini-IR collaboration on this discovery!

This AAVSO Alert Notice was compiled 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 07:28 on 19 September 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


AB Dra
EX Dra
SDSS J153634.42+332851.9

V391 Lyr
V368 Peg
V521 Peg  (UGSU)
CRTS J014709.7+171520
CRTS J021110.2+171624
RX J0044.3+4134 : (UGWZ, fourth observed rebrightening? Please take further snapshots)

AS Pav
V537 Peg
UZ Ser

Current superoutbursts (since ...)
ASASSN-14et (20200902, UGSU)
ASASSN-15qr (20200902, UGSU)
CTCV J2056-3014 :# (20200902, intermediate polar, Porb= 0.0732 d (105.4 min))
ASASSN-13br (20200828, UGSU)
V630 Cyg (20200826, UGSU)
ASASSN-20kv # (20200826, UGWZ, superhump period 0.0555(2) d)
ASASSN-13ct (20200824)
TT Boo (20200818, UGSU)
BC UMa # (20200816, UGWZ, rebrightening 20200902)
ASASSN-20jx # (20200813, UGWZ:, rebrightenings on 20200903/04 and 0906/07)
AY For (20200811, UGSU, eclipsing, orbital period 0.07460 d = 107.42 min)
MASTER OT J001436.25+503240.3 : (20200810, UGSU:, time-resolved photometry is required)
V650 Peg (20200808, UGSU)
ASASSN-18acf (20200808, UGSU)
ASASSN-19fy (20200805, UGSU, rebrightenings on 20200820 and 20200828)
ASASSN-20jl :# (20200731, UGWZ:, time-resolved photometry is urgently required)
ASASSN-17dg (20200713)
ASASSN-14cv # (20200710; UGWZ, rebrightenings on 20200729, 0802, 0808, and 0812)
PQ And # (20200528; UGWZ:, first recorded outburst since discovery in 1988)
Gaia20cfj (20200509)
SDSS J124058.03-015919.2 # (20200429; AM CVn star, 7 rebrightenings, Psh= 0.02598(5) d) 

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.


19 September 2020

For new papers on CV's see astro-ph

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