Astron. Astrophys. 343, 909-915 (1999)

1. Introduction

The history of close study of the cataclysmic variable MV Lyr spans half a century. MV Lyr was discovered as a variable star by Parenago (1946) and independently by MacRae (1952). It is a very blue nova-like star, clearly showing two brightness states: a high state with , , and a low one with , , (Walker 1954, Romano & Rosino 1980, Robinson et al. 1981).

It is often classified among the VY Scl stars or "anti-dwarf-novae", which spend their time mostly in a high brightness state and abruptly fall to faint states for a short time. However, during the last 20 years MV Lyr has behaved somewhat differently. In 1979 the star fell to a minimum which lasted 10 years. In that state MV Lyr showed outbursts of amplitude , but never reached its familiar high state. Outbursts can be divided into three types (Shugarov & Pavlenko 1998): most have "half widths" days, some days, and a very few about 100 days. In 1989 the star moved to its high state, which lasted until 1995. Since then MV Lyr has remained in a low state with its trademark signature of flares.

© European Southern Observatory (ESO) 1999

Online publication: March 1, 1999
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