2020AJ....159...29W


Query : 2020AJ....159...29W

2020AJ....159...29W - Astron. J., 159, 29-29 (2020/January-0)

The full Kepler phase curve of the eclipsing hot white dwarf binary system KOI-964.

WONG I., SHPORER A., BECKER J.C., FULTON B.J., BERGER T.A., WEINBERG N.N., ARRAS P., HOWARD A.W. and BENNEKE B.

Abstract (from CDS):

We analyze the full Kepler phase curve of KOI-964, a binary system consisting of a hot white dwarf on an eclipsing orbit around an A-type host star. Using all 18 quarters of long-cadence photometry, we carry out a joint light-curve fit and obtain improved phase-curve amplitudes, occultation depths, orbital parameters, and transit ephemeris over the previous results of Carter et al. A periodogram of the residuals from the phase-curve fit reveals an additional stellar variability signal from the host star with a characteristic period of 0.620276 ± 0.000011 days and a full amplitude of 24 ± 2 ppm. We also present new Keck/HIRES radial velocity observations, which we use to measure the orbit and obtain a mass ratio of q = 0.106 ± 0.012. Combining this measurement with the results of a stellar isochrone analysis, we find that the masses of the host star and white dwarf companion are 2.23 ± 0.12 M and 0.236–0.027+0.028M, respectively. The effective temperatures of the two components are 9940–230+260 K and 15,080 ± 400 K, respectively, and we determine the age of the system to be 0.21–0.08+0.11 Gyr. We use the measured system properties to compute predicted phase-curve amplitudes and find that while the measured Doppler-boosting and mutual illumination components agree well with theory, the ellipsoidal distortion amplitude is significantly underestimated. We detail possible explanations for this discrepancy, including interactions between the dynamical tide of the host star and the tidal bulge and possible nonsynchronous rotation of the host star.

Abstract Copyright: © 2019. The American Astronomical Society. All rights reserved.

Journal keyword(s): Eclipsing binary stars

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 KOI-964 EB* 19 13 59.8696461528 +47 59 47.244395688           ~ 48 0
2 KOI-81 EB* 19 35 08.5764186408 +45 01 06.455313660   11.51 11.32     B8V 53 0
3 HD 187091 EB* 19 46 15.5312943504 +43 56 51.341798220   8.53 8.39     kA3hA5mA5(IV)sAm: 85 0
4 KOI-74 EB* 19 53 17.8104467976 +42 23 18.509696700   10.832 10.896 10.976   A1V 61 1

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