Discovery of a stripped red giant core in a bright eclipsing binary system

Maxted PFL, Anderson DR, Burleigh MR, Cameron AC, Heber U, Gaensicke BT, Geier S, Kupfer T, Marsh TR, Nelemans G, O'Toole SJ, Ostensen RH, Smalley B, West RG (2011)

Publication Type: Journal article

Publication year: 2011

Journal

Monthly Notices of the Royal Astronomical Society Oxford University Press

Book Volume: 418

Pages Range: 1156-1164

Journal Issue: 2

DOI: 10.1111/j.1365-2966.2011.19567.x

Abstract

We have identified a star in the Wide Angle Search for Planets (WASP) archive photometry with an unusual light curve due to the total eclipse of a small, hot star by an apparently normal A-type star and with an orbital period of only 0.668d. From an analysis of the WASP light curve together with V-band and IC-band photometry of the eclipse and a spectroscopic orbit for the A-type star we estimate that the companion star has a mass of 0.23 ± 0.03M⊙ and a radius of 0.33 ± 0.01R⊙, assuming that the A-type star is a main-sequence star with the metallicity appropriate for a thick-disc star. The effective temperature of the companion is 13400 ± 1200K from which we infer a luminosity of 3 ± 1L⊙. From a comparison of these parameters to various models we conclude that the companion is most likely to be the remnant of a red giant star that has been very recently stripped of its outer layers by mass transfer on to the A-type star. In this scenario, the companion is currently in a shell hydrogen-burning phase of its evolution, evolving at nearly constant luminosity to hotter effective temperatures prior to ceasing hydrogen burning and fading to become a low-mass white dwarf composed of helium (He-WD). The system will then resemble the pre-He-WD/He-WD companions to A- and B-type stars recently identified from their Kepler satellite light curves (KOI-74, KOI-81 and KIC10657664). This newly discovered binary offers the opportunity to study the evolution of a stripped red giant star through the pre-He-WD stage in great detail. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Authors with CRIS profile

Ulrich Heber Naturwissenschaftliche Fakultät Stephan Geier Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut

Involved external institutions

University of Warwick GB United Kingdom (GB) University of Keele GB United Kingdom (GB) Katholieke Universiteit Leuven (KUL) / Catholic University of Leuven BE Belgium (BE) University of Leicester GB United Kingdom (GB) Radboud University Nijmegen NL Netherlands (NL) Australian Astronomical Observatory AU Australia (AU) University of St Andrews GB United Kingdom (GB)

How to cite

APA:

Maxted, P.F.L., Anderson, D.R., Burleigh, M.R., Cameron, A.C., Heber, U., Gaensicke, B.T.,... West, R.G. (2011). Discovery of a stripped red giant core in a bright eclipsing binary system. Monthly Notices of the Royal Astronomical Society, 418(2), 1156-1164. https://doi.org/10.1111/j.1365-2966.2011.19567.x

MLA:

Maxted, P. F. L., et al. "Discovery of a stripped red giant core in a bright eclipsing binary system." Monthly Notices of the Royal Astronomical Society 418.2 (2011): 1156-1164.

BibTeX: Download