Period and amplitude variations in post-common-envelope eclipsing binaries observed with SuperWASP^⋆

¹ Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
e-mail: Marcus.Lohr@open.ac.uk
² Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
³ SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, Fife KY16 9SS, UK
⁴ Department of Physics, University of Warwick, Coventry CV4 7AL, UK
⁵ Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
⁶ Isaac Newton Group of Telescopes, Apartado de Correos 321, 38700 Santa Cruz de la Palma, Tenerife, Spain

Received: 17 April 2014
Accepted: 16 May 2014

Abstract

Period or amplitude variations in eclipsing binaries may reveal the presence of additional massive bodies in the system, such as circumbinary planets. Here, we have studied twelve previously-known eclipsing post-common-envelope binaries for evidence of such light curve variations, on the basis of multi-year observations in the SuperWASP archive. The results for HW Vir provided strong evidence for period changes consistent with those measured by previous studies, and help support a two-planet model for the system. ASAS J102322−3737.0 exhibited plausible evidence for a period increase not previously suggested; while NY Vir, QS Vir and NSVS 14256825 afforded less significant support for period change, providing some confirmation to earlier claims. In other cases, period change was not convincingly observed; for AA Dor and NSVS 07826147, previous findings of constant period were confirmed. This study allows us to present hundreds of new primary eclipse timings for these systems, and further demonstrates the value of wide-field high-cadence surveys like SuperWASP for the investigation of variable stars.