High-speed photometry of the pre-cataclysmic binary HW Virginis and its orbital period change

被引:15
|
作者
Ibanoglu, C [1 ]
Çakirli, Ö [1 ]
Tas, G [1 ]
Evren, S [1 ]
机构
[1] Ege Univ Observ, TR-35100 Izmir, Turkey
关键词
stars : individual : HW Vir; stars : binaries : eclipsing; techniques : photometry;
D O I
10.1051/0004-6361:20034013
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The broad band B and V light curves of the pre-cataclysmic eclipsing binary HW Vir were obtained. All the available eclipse timings, including the new ones, spanning 19 years were analyzed under the third-body hypothesis. The residuals between the observed and calculated times of mid-eclipse show a long-term sinusoidal variation. The analysis yields the parameters of the third-body orbit, as well as limiting mass for the tertiary object. The result of this analysis gives a light-time semi-amplitude of 112 s. an orbital period of 18.8 yr and an eccentricity of 0.12. The mass of the third star is below the theoretical threshold of 0.07 M(.) for a hydrogen burning star. Its minimum mass is about 0.022 M(.) and for a wide range of inclinations of third-body orbit, i.e. i greater than or equal to 19degrees, the mass is smaller than 0.07 M(.). Therefore, we suggest that the third star may be a brown dwarf candidate. Combining the semi-amplitudes of the radial velocities and the photometric light curve solution has allowed us to model the short-period detached binary HW Vir. The luminosity and radius of the dM companion are slightly larger than that given by low-mass models.
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页码:1043 / 1048
页数:6
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