Two X-ray bright cataclysmic variables with unusual activities: GZ Cnc and NSV 10934

¹ Department of Astronomy, Kyoto University, Kyoto 606-8502, Japan
² MEDUZA group, Vedecko-kulturne centrum na Orave, 027 42 Podbiel 194, Slovakia
³ 19 Greenland Drive, Drouin 3818, Victoria, Australia
⁴ 46394 Roanne Drive Macomb, MI 48044, USA
⁵ Faculty of Science, Kyushu University, Fukuoka 810-8560, Japan
⁶ RMB 2493, Ellinbank 3820, Australia
⁷ Bronberg Observatory, PO Box 11426, Tiegerpoort 0056, South Africa
⁸ 32 Monash Ave, Nedlands, WA 6009, Australia
⁹ PO Box 157, NSW 2340, Australia

Corresponding author: T. Kato, tkato@kusastro.kyoto-u.ac.jp

Received: 29 August 2002
Accepted: 1 October 2002

Abstract

We report on a discovery of unexpected activities in two X-ray bright dwarf novae. GZ Cnc showed an anomalous clustering of outbursts in 2002, in contrast to a low outburst frequency in the past record. The activity resembles an increased activity seen in some intermediate polars or candidates. We identified NSV 10934, X-ray selected high-amplitude variable star, as a dwarf nova with unusually rapid decline. The outburst characteristics make NSV 10934 a twin of recently discovered intermediate polar (HT Cam) with dwarf nova-type outbursts. We propose that these activities in X-ray strong dwarf novae may be a previously overlooked manifestation of outburst activities in magnetic cataclysmic variables.