KOI 1224: A FOURTH BLOATED HOT WHITE DWARF COMPANION FOUND WITHKEPLER
- 14 March 2012
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 748 (2)
- https://doi.org/10.1088/0004-637x/748/2/115
Abstract
We present an analysis and interpretation of the Kepler binary system KOI 1224. This is the fourth binary found with Kepler that consists of a thermally bloated, hot white dwarf in a close orbit with a more or less normal star of spectral class A or F. As we show, KOI 1224 contains a white dwarf with T-eff = 14,700 +/- 1000 K, mass = 0.22 +/- 0.02 M-circle dot, and radius = 0.103 +/- 0.002 R-circle dot, and an F-star companion of mass 1.59 +/- 0.06 M-circle dot that is somewhat beyond its terminal-age main sequence. The orbital period is quite short at 2.69802 days. The ingredients that are used in the analysis are the Kepler binary light curve, including the detection of the Doppler boosting effect; the NUV and FUV fluxes from the GALEX images of this object; an estimate of the spectral type of the F-star companion; and evolutionary models of the companion designed to match its effective temperature and mean density. The light curve is modeled with a new code named Icarus which we describe in detail. Its features include the full treatment of orbital phase-resolved spectroscopy, Doppler boosting, irradiation effects, and transits/eclipses, which are particularly suited to irradiated eclipsing binaries. We interpret the KOI 1224 system in terms of its likely evolutionary history. We infer that this type of system, containing a bloated hot white dwarf, is the direct descendant of an Algol-type binary. In spite of this basic understanding of the origin of KOI 1224, we discuss a number of problems associated with producing a system with an orbital period this short.This publication has 49 references indexed in Scilit:
- KEPLERINPUT CATALOG: PHOTOMETRIC CALIBRATION AND STELLAR CLASSIFICATIONThe Astronomical Journal, 2011
- CHARACTERISTICS OF PLANETARY CANDIDATES OBSERVED BYKEPLER. II. ANALYSIS OF THE FIRST FOUR MONTHS OF DATAThe Astrophysical Journal, 2011
- COLDER AND HOTTER: INTERFEROMETRIC IMAGING OF β CASSIOPEIAE AND α LEONISThe Astrophysical Journal, 2011
- A THIRD HOT WHITE DWARF COMPANION DETECTED BYKEPLERThe Astrophysical Journal, 2011
- Statistical Properties of the GALEX ‐SDSS Matched Source Catalogs, and Classification of the UV SourcesThe Astrophysical Journal Supplement Series, 2007
- Stellar SEDs from 0.3 to 2.5 μm: Tracing the Stellar Locus and Searching for Color Outliers in the SDSS and 2MASSThe Astronomical Journal, 2007
- K–H2 quasi-molecular absorption detected in the T-dwarf $\mathsf{\varepsilon}$ Indi BaAstronomy & Astrophysics, 2007
- Allen’s Astrophysical QuantitiesPublished by Springer Science and Business Media LLC ,2002
- The ellipsoidal variablesAstrophysics and Space Science, 1985
- Ellipsoidal light variations and masses of X-ray binariesThe Astrophysical Journal, 1975