NOAO >   Observing Info >   Approved Programs >   2010B-0279

# Proposal Information for 2010B-0279

PI: Ryan K. Campbell, CTIO/NOAO, eddywitten@gmail.com
Address: Science, 950 N. Cherry Ave., Tucson, AZ 85719, USA

CoI: Thomas E. Harrison, New Mexico State Univ.
CoI: Paula Szkody, University of Washington
CoI: Steve Howell, NOAO

Title: Addressing Fundamental Issues in LARPS

Abstract: We have used GALEX to show that the Low Accretion Rate Polars (LARPS") have significant UV/Optical variability in excess of what can be explained with a simple hotspot model. One plausible explanation is ongoing cyclotron emission in these systems. While previous optical spectroscopy has revealed the presence of cyclotron features in many LARPs, those data were inadequate for a conclusive determination of cyclotron emission and for subsequent modeling purposes for the targets we have selected for the current proposal. We propose to obtain new, phase-resolved optical spectroscopy of two LARPS: WX LMi, and SDSS J1212 and one LARP intermediary: EF Eri. Our targets have magnitudes of V=17.0 - 18.0, and orbital periods of several hours. Thus, we require two full nights to achieve adequate phase-sampling ((Delta) \phi=0.05 P_orb ) with sufficient S/N for each phase-point. The resulting data will be modeled with our Structured-Shock" cyclotron code to determine the magnetic field strength, geometry, accretion parameters as well as the Roche Filling Factor (\Omega_S ) which places constraints on the feasibility of wind-fed accretion in LARPS, and by extension the binary evolutionary scenario.

National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360

 NOAO >   Observing Info >   Approved Programs >   2010B-0279