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. | Last updated 07:00 on 23 October 2020 (All objects mentioned in this section are in the International Variable Star Index; additionally, VSX links have been given for selected cataclysmic variables) YYYYMMDD 20201022 IX Dra V476 Peg V537 Peg VW Vul 20201021 SS Aur WW Cet ASASSN-17cp CRTS J081418.9-005022 20201020 SY Cnc V792 Cyg V1006 Cyg LT Eri NSV 2026 ASASSN-15bu (UGSU, eclipsing, orbital period 0.07681907 d = 110.61946 min) ASASSN-14ff CSS J062450.0+503111 Current superoutbursts (since ...) AY Lac # (20201008, UGWZ, time-resolved photometry is urgently required) KK Cnc # (20201003, UGWZ) ASASSN-14en (20201001, UGSU, uperhump period 0.0674(9) d) V521 Peg (20200917, UGSU) ASASSN-14av : (20200917, UGSU:) 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) # 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. RECENT PAPERS ON CVs 16 October 2020 For new papers on CV's see arxiv.org 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 U. Munari, S. Moretti, A. Maitan 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 Susanne M Hoffmann, Nikolaus Vogt 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 Mariko Kimura, Yoji Osaki, Taichi Kato, Shin Mineshige Raymundo Baptista, Eduardo Wojcikiewicz 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 |
