NOAO >   Observing Info >   Approved Programs >   2003B-0004

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Proposal Information for 2003B-0004


PI: Donald W. Hoard, California Institute of Technology, hoard@ipac.caltech.edu
Address: SIRTF Science Center, MC 220-6, 1200 E. California Blvd., Pasadena, CA 91125, USA

CoI: Stefanie Wachter, California Institute of Technology

Title: Long-term Variability of the Unusual Double-lined Cataclysmic Variable CM Phe

Abstract: We propose to use the CTIO 1.3-m telescope to obtain long-term synoptic optical and IR light curves of the unusual double-lined cataclysmic variable (CV) CM Phe. We previously used the CTIO 0.9-m telescope to discover the orbital period of 0.2683 d for this CV. Our new long-term light curves will be used to monitor, characterize, and compare the substantial night-to-night variability seen in past short (< 1 week) light curves and in our successful YALO monitoring campaign from the 2001B observing season. In addition, during 2001B we observed an abrupt transition from bright (V~15.2) to faint (V~16.4) state. Our YALO data show a ``failed attempt'' to return to the bright state (lasting ~80 d), but the CV did not fully return to the bright state during our 2001B monitoring. We hope to observe a repeat of (or the recovery from) the state change phenomenon during 2003B. The wide range of variability profiles and time scales observed in CM Phe is exceptional even for a CV, and may be caused by changes in the mass transfer properties linked to solar-like activity on the (possibly evolved) secondary star.


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