The Kepler and Hale observations of V523 Lyr

Abstract

We present new observations of the cataclysmic variable V523 Lyr, a member of the open cluster NGC 6791. The Kepler Space telescope obtained photometric observations of this source and we examine the nearly 3 year long light curve. The observations show numerous small amplitude outbursts recurring on average every 33 days, intermittent quasi-periodic oscillations, and a significant fully coherent period of ~3.8 hr which we identify as the orbital period of the binary. Contemporaneous optical spectroscopy of V523 Lyr reveals a faint blue source with broad Balmer absorption lines containing narrow emission cores. H$α$ is in emission above the continuum. The low amplitude of the photometric signal and no detected velocity motion suggest a low orbital inclination. We discuss the properties of V523 Lyr and show that it is a member of the growing group of anomalous Z Cam type CVs, systems which show stunted outbursts, light curve standstills, and occasional deep drops in brightness.

Accepted for publication in A&A on 28/02/2016