[vsnet-alert 25094] ZTF20acufmah (= ATLAS20bgit, ASASSN-20oz): superoutburst started on Nov. 29

Fri Dec 11 05:07:45 JST 2020

 ZTF20acufmah (UGSU)
https://www.aavso.org/vsx/index.php?view=detail.top&oid=2214294

The current superoutburst started on 2020 Nov. 29 (according
to ZTF data). A previous superoutburst was observed by the
ASAS-SN Sky Patrol from 2016 Jan. 28 to Feb. 1 (but lasted
presumably for several more days) [see also my VSX remark].

Complete ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S
and Kochanek et al. 2017PASP..129j4502K) light curve and data:
https://asas-sn.osu.edu/light_curves/065134cb-1d60-45c3-a092-bf892bbd6cdf

Zwicky Transient Facility (ZTF) light curve and data:
https://lasair.roe.ac.uk/object/ZTF20acufmah/

"Spectroscopic classification of the transient ZTF20acufmah
= AT 2020abfk as a dwarf nova" (ATel #14258):
http://www.astronomerstelegram.org/?read=14258

Further time-resolved photometry is encouraged.

Clear skies,
Patrick
-------     Am Mittwoch, 9. Dezember 2020, 21:06:07 MEZ hat Tonny Vanmunster tonny.vanmunster at gmail.com via vsnet-alert <vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp> Folgendes geschrieben:  

 Dear colleagues,

I have just finished analysing my unfiltered CCD observations of ASASSN-20oz, obtained last night (2020, Dec 08/09) at CBA Extremadura Observatory, using a 0.40-m f/5.1 telescope and SX-46 CCD camera under clear skies. 

Superhumps with an amplitude of 0.23 mag are clearly visible in the resulting light curve, establishing ASASSN-20oz as a new SU UMa-type dwarf nova. A period analysis using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.0, release end of December), yields a combined superhump period of 0.0598 +/- 0.0007d. The object was at mag 16.3 (CV) on Dec 08th.

The superhump profile shows a possible (but weak) double-waved pattern, leaving open the possibility that this is a WZ Sge-type dwarf nova. Follow-up observations are recommended to further analyse this.

I will send my observations (currently large backlog) to AAVSO, CBA and VSNET for further analysis.

Best regards
Tonny

--
Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory
www.cbabelgium.com
www.peranso.com

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