High Speed Optical Photometry of the LMXB UW CrB: An improved Limit on the Orbital Period Derivative

POSTER

Abstract

We present new broad band optical photometry of the low mass X-ray binary (LMXB) UW CrB on four consecutive nights in June 2013. These data were obtained at the 2.1-m telescope of McDonald Observatory and have a time resolution of 10s and cover a bit more than one orbital cycle each night. The light curves display partial eclipses of the accretion disk by the donor star that vary both in depth and orbital phase in the same manner as has been previously reported. Analysis of the new eclipse times in conjunction with published eclipse timings are well fitted with a linear ephemeris. We derive an upper limit on the time derivative of the orbital period, based on the best fit quadratic ephemeris, and discuss its implications on the average mass transfer rate. By including the newly observed type I bursts with published bursts in our analysis, we find that bursts are not observed between 0.93 and 0.07 phases, i.e. they are not observable during partial eclipses of the disk.

Authors

  • Jacob Segura

    Univ of Texas, El Paso

  • Paul Mason

    Univ of Texas, El Paso

  • Hanu Arava

    University of Houston, University of Texas at Brownsville, None, Univ of Texas, San Antonio, University of Texas at El Paso, Univ of Arizona, Department of Physics and Astronomy and Center for Gravitational Wave Astronomy, University of Texas at Brownsville, Laboratoire des Mat\'eriaux Avanc\'es, Universit\'e Claude Bernard Lyon 1, UTEP, University of Texas, Austin, University of Texas at Austin, Institute for Astronomy, Russian Academy of Sciences, University of Texas at Arlington, The University of Texas at Arlington, MIT, U. Mass. Dartmouth, Texas A{\&}M University, Texas Christian University, Laboratoire des Mat\'erieux Avanc\'es B\^atiment Virgo, Ion Beam Materials Laboratory, Los Alamos National Laboratory, Texas A\&M University, Accelerator Research Laboratory, University of Florida, The Ohio State University, Yale University, University of Guelph, Canada, Armagh Observatory, NASA-Ames, NASA-Goddard, Texas A\&M University-Commerce, Texas A\&M University, Hanyang University, Texas A\&M Univ, Department of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran, Physics Department, Texas State University at San Marcos