Discovery of a stripped red giant core in a bright eclipsing binary system
Maxted, P. F. L., Anderson, D. R., Burleigh, Matthew R., Collier Cameron, A., Heber, U. (Ulrich), 1954-, Gänsicke, B. T. (Boris T.), Geier, S., Kupfer, T., Marsh, T. R., Nelemans, G., O’Toole, S. J., Østensen, R. H., Smalley, B. and West, R. G.. (2011) Discovery of a stripped red giant core in a bright eclipsing binary system. Monthly Notices of the Royal Astronomical Society, Vol.418 (No.2). pp. 1156-1164. ISSN 0035-8711Full text not available from this repository.
Official URL: http://dx.doi.org/10.1111/j.1365-2966.2011.19567.x
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 0.668 d. 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 ± 0.03 M⊙ and a radius of 0.33 ± 0.01 R⊙, 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 13 400 ± 1200 K from which we infer a luminosity of 3 ± 1 L⊙. 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 KIC 10657664). 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.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Library of Congress Subject Headings (LCSH):||Double stars, Eclipsing binaries, Double stars -- Spectra, Peculiar stars, Red giants|
|Journal or Publication Title:||Monthly Notices of the Royal Astronomical Society|
|Official Date:||December 2011|
|Page Range:||pp. 1156-1164|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Science and Technology Facilities Council (Great Britain) (STFC), United States. National Aeronautics and Space Administration (NASA), National Science Foundation (U.S.) (NSF)|
Ag¨ueros M. A., Camilo F., Silvestri N. M., Kleinman S. J., Anderson S. F.,
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