Special Notice #386: ASASSN-14cl New large-amplitude cataclysmic variable

June 20, 2014: Kris Z. Stanek (The Ohio State University) et al. reported the discovery during the ongoing All-Sky Automated Survey for SuperNovae (ASAS-SN) of a bright transient (10.66V) on 2014 June 14.52 UT. Data were obtained using the quadruple 14-cm "Brutus" telescope in Haleakala, HI (hosted by Las Cumbres Observatory Global Telescope Network).(ATel #6233, http://www.astronomerstelegram.org/?read=6233)

Stanek et al. also report that the object is identified with SDSS J215457.68+264112.7 (g=18.8, r=18.7), which is also designated USNO-B1.0 1166-0570046. The amplitude indicates the object may be a WZ Sge-type cataclysmic variable.

Coordinates: R.A. 21 54 57.70  Dec. +26 41 13.0 (2000.0)

Spectroscopy by Francois Teyssier (ARAS; Rouen, France) obtained on June 15.0 UT and reported in ATel #6235 (http://www.astronomerstelegram.org/?read=6235) shows that ASASSN-14cl is a dwarf nova in outburst. Spectra may be downloaded via the Astronomical Ring for Access to Spectroscopy (ARAS) site at http://www.astrosurf.com/aras/Aras_DataBase/Cataclysmics/_asassn-14cl_20140615_000_fteyssier.fit

Observations by Arto Oksanen (Muurame, Finland) and Colin Littlefield (South Bend, IN) show <0.1-magnitude amplitude variations, which may be related to early superhump formation. Nick James (Chelmsford, England) reports a possible superhump period from his observations made around June 19.0804 UT that is different from earlier values published but indicates the difference may be due to insufficient data on his part.

11 observers have contributed over 4,000 B/V/TB/TG and visual observations to the AAVSO International Database to date. The earliest observations reported to the AAVSO include:
2014 June 13.5 UT, <16.2 V (ASASSN);
14.91180, 10.5 visual (W. Kriebel, Schierling/Walkenstetten, Germany);
15.059, 10.6 visual (P. Schmeer, Bischmisheim, Germany);
15.18567, 10.702 V +/-0.004 (A. Oksanen, Muurame, Finland);
15.18653, 10.664 V +/-0.004 (Oksanen);

The most recent observations are:
2014 June 18.90760, 11.8 visual (Kriebel);
18.99306, 11.9 visual (K. Wenzel, Grossostheim, Germany);
20.25970, 11.9 visual (M. Komorous, London, ONT, Canada);

Finder charts with a sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp).

A new sequence has been posted for this object. Observers who have already submitted data should check their data to see if they need to re-reduce their photometry.

Please report observations to the AAVSO International Database using the name ASASSN-14cl.

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.


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