CVnet - Cataclysmic Variables Network

AAVSO Alert Notice 706
Nova in Sagittarius: Nova Sagittarii 2020 No. 2 = ASASSN-20ga
8 June 2020

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Time Sensitive Alerts:
- Novae: highly reddened galactic classical nova in Sagittarius

Event: Nova in Sagittarius: N Sgr 2020 No. 2 = ASASSN-20ga = PGIR20dsv = ZTF20abdpwst = AT 2020lrv

Discovered by: All-Sky Automated Survey for Supernovae (ASAS-SN)

Discovery magnitude: 15.3 g

Discovery date: 2020 June 2.26 UT

Coordinates (2000.0): R.A. 18 22 45.33    Decl. -19 36 02.3   (from VSX page for ASASSN-20ga)

Spectra: Spectroscopy obtained on 2020 June 8 UT by De et al. using the SED Machine spectrograph on the Palomar 60-inch telescope indicates that the object is a highly reddened Galactic classical nova (announced in ATel #13790, De et al. 2020). ASASSN-20ga is the second Galactic nova discovered in Sagittarius in 2020.

Observing recommendations: Observations of all types (visual, CCD, DSLR, spectroscopy) and multiple bands as instrumentation permits are strongly encouraged as the nova evolves.

Observations reported to the AAVSO:
2020 May 28 UT, <13 AB (J mag, Palomar Gattini-IR survey; see Note b re magnitude, via ATel #13790)
28.3782, 19.618 g (Zwicky Transient Factory, ZTF20abdpwst);
31.3549, 17.260 r (Zwicky Transient Factory, ZTF20abdpwst);
31.4178, 15.807 g ± 0.089 (Zwicky Transient Factory, ZTF20abdpwst);
Jun 1, 11.16 +/- 0.07 AB mag (J mag, Palomar Gattini-IR survey; via ATel #13790)
02.06, 15 V/g (ASAS-SN)
04, 11.69 AB +/- 0.07 (J mag, Palomar Gattini-IR survey; via ATel #13790)
05.29378, 14.267 CV +/-0.023 (J.-F. Hambsch, Mol, Belgium; Hambsch observations are selected from 133 observations made over three nights);
05.29683, 14.248 CV +/-0.023 (Hambsch);
05.29986, 14.281 CV +/-0.024 (Hambsch);
05.30292, 14.259 CV +/-0.038 (Hambsch);
05.33043, 14.250 CV +/-0.024 (Hambsch);
05.37993, 14.264 CV +/-0.022 (Hambsch);
05.38229, 14.236 CV +/-0.024 (Hambsch);
05.42464, 14.225 CV +/-0.022 (Hambsch);
05.42701, 14.253 CV +/-0.053 (Hambsch);
05.42936, 14.264 CV +/-0.069 (Hambsch);
05.43170, 14.236 CV +/-0.073 (Hambsch);
06.29412, 14.231 CV +/-0.094 (Hambsch);
06.29721, 14.163 CV +/-0.086 (Hambsch);
06.30030, 14.145 CV +/-0.097 (Hambsch);
06.32811, 14.171 CV +/-0.087 (Hambsch);
06.33123, 14.237 CV +/-0.090 (Hambsch);
06.33743, 14.073 CV +/-0.074 (Hambsch);
06.35131, 14.204 CV +/-0.068 (Hambsch);
06.36794, 14.295 CV +/-0.080 (Hambsch);
06.37977, 14.119 CV +/-0.132 (Hambsch);
06.39162, 14.100 CV +/-0.169 (Hambsch);
06.41779, 14.293 CV +/-0.087 (Hambsch);
08.28550, 14.320 CV +/-0.059 (Hambsch);
08.28854, 14.282 CV +/-0.026 (Hambsch);
08.31006, 14.257 CV +/-0.026 (Hambsch);
08.31314, 14.289 CV +/-0.058 (Hambsch);
08.31622, 14.281 CV +/-0.062 (Hambsch);
08.32543, 14.334 CV +/-0.060 (Hambsch);
08.42370, 14.228 CV +/-0.072 (Hambsch);
08.42609, 14.308 CV +/-0.081 (Hambsch);
08.42845, 14.427 CV +/-0.074 (Hambsch);
08.43081, 14.424 CV +/-0.087 (Hambsch);
08.43316, 14.209 CV +/-0.084 (Hambsch);

Charts: Charts with comparison stars for N Sgr 2020 No. 2 may be created using the AAVSO Variable Star Plotter (VSP).

Submit observations: Please submit observations to the AAVSO International Database using the name N Sgr 2020 No. 2. When a GCVS name is assigned to this nova, please use it when submitting observations.

a. Some of the information in this AAVSO Alert Notice is taken from ATel #13790.

b. Palomar Gattini-IR (PGIR) is a wide-field NIR transient survey scanning the entire Northern sky in J band to a median depth of 15.7 AB mag every two nights (ATel #13790).

c. De et al. report (ATel #13790) that "the integrated extinction along this line of sight is ~ 6 mags in g band, ~ 4 mags in r band and ~ 1 mag in J band (Schlafly et al. 2011)."

d. De et al. report (ATel #13790) that there is no source reported at position end figures 45.2s, 02.6" in archival 2MASS images.

Congratulations to the ASAS-SN survey team on this discovery!

This Alert Notice was compiled by Elizabeth O. Waagen.

AAVSO Alert Notice 705: Rare outburst of the WZ Sge star PQ Andromedae (Nova And 1988)
29 May 2020

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

Observers are encouraged to participate in the AAVSO forums listed above for this event, and to visit the AAVSO CV Section webpage. Also, observers can find AAVSO-related information on current CV activity at

Event: Rare outburst of the WZ Sagittae-type dwarf nova PQ Andromedae ("Nova" Andromedae 1988)

Discovered by: Kenji Hirosawa (Aichi, Japan)

Discovery magnitude: 10.48 cG (using 20cmL (FL 1000mm) + CANON X9)
Discovery date: 2020 May 28.77633 UT

Coordinates (2000.0): R.A. 02 29 29.57   Decl. +40 02 39.8  (from VSX page)

Discussion: PQ And was discovered as Nova And 1988 on March 21 by David McAdam (Telford, UK; IAUC 4570). It was presumed to be a nova (IAUC 4620) but as the spectrum was lost after initial review it was not available for additional study.

PQ And is now known to be a WZ Sge-type system (UGWZ+ZZ/GWLIB) and may be a period bouncer (Patterson et al. 2005, Publ. Astron. Soc. Pac., 117, 922). Previous outbursts were found by G. A. Richter on archival photographic plates taken in 1938 and 1967 (1990, IBVS No. 3546).

Observing recommendations: Time series are requested; the orbital period is 0.0560 d (80.6 min) so the cadence should be determined accordingly. Filtered photometry is preferred. PQ And is presently a morning target and difficult to observe, but observations made now are very important to capture superhump development.

Spectroscopy is also requested.

Observations reported to the AAVSO:
2020 Mar. 16.84030, <14.0 (E. Muyllaert, Oostende, Belgium);
19.81460, <14.5 (C. Allen, Farjestaden, Sweden);
22.85830, <14.5 (Allen);
Apr. 25.83472, <11.9 (P. Schmeer, Saarbrücken-Bischmisheim, Germany);
May. 28.77633, 10.48 cG (K. Hirosawa, Aichi, Japan; discovery (via [vsnet-alert 24302], see Note a);
29.07990, 10.3 (Muyllaert; confirmation);
29.088, 10.5 (G. Poyner, Birmingham, UK);
29.09375, 10.7 (Schmeer);

Charts: Charts with comparison stars for PQ And may be created using the AAVSO Variable Star  Plotter (VSP). Please be sure to check VSP to make certain you have the latest version.

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

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

a. Hirosawa's original discovery announcement stated the date incorrectly as 20200528.27633 in [vsnet-alert 24301].

Congratulations to Kenji Hirosawa on his discovery of this rare outburst!

This Alert Notice was compiled by Elizabeth O. Waagen.

The Z CamPaign

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 07:02 on 9 July 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


MASTER OT J183342.09+654019.1

PQ And (Fourth rebrightening)

Current superoutbursts (since ...)
KK Tel (20200625, UGSU)
ASASSN-16it (20200622, UGSU)
TY Vul (20200621, UGSU)
ASASSN-13bm (20200620, UGSU)
UV Per (20200620, UGSU)
BC Dor (20200619, UGSU)
TCP J02041514+4053325 # (20200616; UGWZ:, time-resolved photometry is required)
AW Sge (20200608, UGSU)
SDSS J155720.75+180720.2 (20200531, UGSU)
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 June 2020

For new papers on CV's see astro-ph

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