2014A&A...567A.124H


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.13CEST06:36:15

2014A&A...567A.124H - Astronomy and Astrophysics, volume 567A, 124-124 (2014/7-1)

HD 51844: An Am δ Scuti in a binary showing periastron brightening.

HARETER M., PAPARO M., WEISS W., GARCIA HERNANDEZ A., BORKOVITS T., LAMPENS P., RAINER M., DE CAT P., MARCOS-ARENAL P., VOS J., PORETTI E., BAGLIN A., MICHEL E., BAUDIN F. and CATALA C.

Abstract (from CDS):

Pulsating stars in binary systems are ideal laboratories to test stellar evolution and pulsation theory, since a direct, model-independent determination of component masses is possible. The high-precision CoRoT photometry allows a detailed view of the frequency content of pulsating stars, enabling detection of patterns in their distribution. The object HD51844 is such a case showing periastron brightening instead of eclipses. We present a comprehensive study of the HD51844 system, where we derive physical parameters of both components, the pulsation content and frequency patterns. Additionally, we obtain the orbital elements, including masses, and the chemical composition of the stars. Time series analysis using standard tools was employed to extract the pulsation frequencies. Photospheric abundances of 21 chemical elements were derived by means of spectrum synthesis. We derived orbital elements both by fitting the observed radial velocities and the light curves, and we did asteroseismic modelling as well. We found that HD51844 is a double lined spectroscopic binary. The determined abundances are consistent with δ Delphini classification. We determined the orbital period (33.498±0.002d), the eccentricity (0.484±0.020), the mass ratio (0.988±0.02), and the masses to 2.0±0.2M for both components. Only one component showed pulsation. Two p modes (f22 and f36) and one g mode (forb) may be tidally excited. Among the 115 frequencies, we detected triplets due to the frequency modulation, frequency differences connected to the orbital period, and unexpected resonances (3:2, 3:5, and 3:4), which is a new discovery for a δ Sct star. The observed frequency differences among the dominant modes suggest a large separation of 2.0-2.2d–1, which are consistent with models of mean density of 0.063g/cm3, and with the binary solution and TAMS evolutionary phase for the pulsating component. The binary evolution is in an intermediate evolutionary phase; the stellar rotation is super-synchronised, but circularisation of the orbit is not reached.

Abstract Copyright:

Journal keyword(s): binaries: spectroscopic - stars: variables: δ Scuti - stars: abundances - stars: individual: HD 51844

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 51844 dS* 06 58 47.3527941560 -04 33 30.361930493   8.97 8.59     kF2mF0 16 0
2 ASAS J190333+3941.0 Al* 19 03 32.7241738858 +39 41 00.368014032   10.95 10.83   10.582 A3V 48 0
3 BD+38 3661 Al* 19 34 46.9048624526 +38 58 58.050206206   9.72 9.28   8.942 F6II 36 0
4 KIC 4847343 EB* 19 39 48.3916629159 +39 55 45.976203017     12.79   12.02 ~ 9 0
5 HD 187091 EB* 19 46 15.5313838595 +43 56 51.339206744   8.53 8.39     kA3hA5mA5(IV)sAm: 56 0
6 HD 190586 EB* 20 03 52.4400818355 +44 11 30.975819880           B9.5III 10 0
7 HD 218396 El* 23 07 28.7156905667 +21 08 03.302133882   6.21 5.953     F0+VkA5mA5 896 0

    Equat.    Gal    SGal    Ecl

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2020.07.13-06:36:15

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