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., Gaensicke, B. T., Geier, S., Kupfer, T., Marsh, T. R., Nelemans, G., O’Toole, S. J., Østensen, R. H., Smalley, B. and West, Richard 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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