Discovery of another Am-Herculis Variable in the Period Gap

Abstract

Recently, Buckley et al. drew attention to a new AM Her variable, RE1938 - , discovered by the ROSAT survey with a period of 2.33 h which places it in the middle of the usual 2-3 h period gap for cataclysmic variables. Here, we report the discovery of yet another AM Her variable, V2009 -65.5, with a period of 2.66 h, also within the period gap. We argue that the anomalously high proportion of AM Hers within the period gap indicates that the canonical magnetic braking mechanism used to explain the orbital evolution of other CVs may not be applicable to the AM Hers. Possible alternative models are discussed.