Copperwheat, C. M., Marsh, T. R., Littlefair, S. P., Dhillon, V. S., Ramsay, G., Drake, A. J., Gaensicke, B. T., Groot, P. J., Hakala, P., Koester, Detlev, Nelemans, G., Roelofs, Gijs H. A., Southworth, J., Steeghs, D. and Tulloch, S. (2010) SDSS J0926+3624 : the shortest period eclipsing binary star. Monthly Notices of the Royal Astronomical Society, Vol.410 (No.2). pp. 1113-1129. doi:10.1111/j.1365-2966.2010.17508.x

Preview

Text WRAP_Steeghs_21_1008.1907v2.pdf - Submitted Version Download (1552Kb) | Preview

Request Changes to record.

Abstract

With orbital periods of the order of tens of minutes or less, the AM Canum Venaticorum stars are ultracompact, hydrogen-deficient binaries with the shortest periods of any binary subclass, and are expected to be among the strongest gravitational wave sources in the sky. To date, the only known eclipsing source of this type is the P= 28 min binary SDSS J0926+3624. We present multiband, high time resolution light curves of this system, collected with William Herschel Telescope (WHT)/ULTRACAM in 2006 and 2009. We supplement these data with additional observations made with Liverpool Telescope/Rapid Imager to Search for Exoplanets (LT/RISE), XMM–Newton and the Catalina Real-Time Transient Survey. From light curve models we determine the mass ratio to be q=M2/M1= 0.041 ± 0.002 and the inclination to be . We calculate the mass of the primary white dwarf to be 0.85 ± 0.04 M⊙ and the donor to be 0.035 ± 0.003 M⊙, implying a partially degenerate state for this component. We observe superhump variations that are characteristic of an elliptical, precessing accretion disc. Our determination of the superhump period excess is in agreement with the established relationship between this parameter and the mass ratio, and is the most precise calibration of this relationship at low q. We also observe a quasi-periodic oscillation in the 2006 data, and we examine the outbursting behaviour of the system over a 4.5 year period.

Item Type:	Journal Article
Subjects:	Q Science > QB Astronomy
Divisions:	Faculty of Science > Physics
Library of Congress Subject Headings (LCSH):	Double stars, Eclipsing binaries, White dwarf stars, Stars, New, Cataclysmic variable stars
Journal or Publication Title:	Monthly Notices of the Royal Astronomical Society
Publisher:	Wiley
ISSN:	0035-8711
Official Date:	January 2010
Dates:	Date Event January 2010 Published
Volume:	Vol.410
Number:	No.2
Page Range:	pp. 1113-1129
DOI:	10.1111/j.1365-2966.2010.17508.x
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
Funder:	Science and Technology Facilities Council (Great Britain) (STFC), European Space Agency (ESA), United States. National Aeronautics and Space Administration (NASA)
Grant number:	ST/F002599/1 (STFC), PP/D002370/1 (STFC), PP/E001777/1 (STFC), NNG05GF22G (NASA)

Request changes or add full text files to a record

Repository staff actions (login required)

View Item

Downloads