2009A&A...508.1375M


Query : 2009A&A...508.1375M

2009A&A...508.1375M - Astronomy and Astrophysics, volume 508, 1375-1389 (2009/12-4)

HD 174884: a strongly eccentric, short-period early-type binary system discovered by CoRoT.

MACERONI C., MONTALBAN J., MICHEL E., HARMANEC P., PRSA A., BRIQUET M., NIEMCZURA E., MOREL T., LADJAL D., AUVERGNE M., BAGLIN A., BAUDIN F., CATALA C., SAMADI R. and AERTS C.

Abstract (from CDS):

Accurate photometric CoRoT space observations of a secondary seismological target, HD 174884, led to the discovery that this star is an astrophysically important double-lined eclipsing spectroscopic binary in an eccentric orbit (e∼0.3), unusual for its short 3.65705d orbital period. The high eccentricity, coupled with the orientation of the binary orbit in space, explains the very unusual observed light curve with strongly unequal primary and secondary eclipses having the depth ratio of 1-to-100 in the CoRoT ``seismo'' passband. Without the high accuracy of the CoRoT photometry, the secondary eclipse, 1.5mmag deep, would have gone unnoticed. A spectroscopic follow-up program provided 45 high dispersion spectra. The analysis of the CoRoT light curve was performed with an adapted version of PHOEBE that supports CoRoT passbands. The final solution was obtained by a simultaneous fitting of the light and the radial velocity curves. Individual star spectra were obtained by spectrum disentangling. The uncertainties of the fit were achieved by bootstrap resampling and the solution uniqueness was tested by heuristic scanning. The results provide a consistent picture of the system composed of two late B stars. The Fourier analysis of the light curve fit residuals yields two components, with orbital frequency multiples and an amplitude of ∼0.1mmag, which are tentatively interpreted as tidally induced pulsations. An extensive comparison with theoretical models is carried out by means of the Levenberg-Marquardt minimization technique, and the discrepancy between the models and the derived parameters is discussed. The best fitting models yield a young system age of 125 million years which is consistent with the eccentric orbit and synchronous component rotation at periastron.

Abstract Copyright:

Journal keyword(s): binaries: close - binaries: eclipsing - stars: fundamental parameters - stars: individual: HD 174884 - stars: variables: general

Simbad objects: 5

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Number of rows : 5
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 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 7084 0
2 HD 50846 SB* 06 54 54.7081653504 -01 22 32.850081768   8.46 8.43     B5/7Ib 149 0
3 HD 313926 EB* 18 09 07.9308992520 -21 28 24.833970444   10.98 10.55     B9 5 0
4 HD 174884 EB* 18 52 40.3063548312 +04 03 11.755214640   8.14 7.998     B8V 39 0
5 HD 177863 SB* 19 07 08.3281460860 -18 44 17.402016979   6.243 6.293     B8V 76 0

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