Improved astrophysical parameters for the overcontact binary FG Hydrae
Improved astrophysical parameters for the overcontact binary FG Hydrae
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DOI：
10.1111/j.1365-2966.2004.08497.x
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发表时间：
2005-01
影响因子：
4.8
通讯作者：
S. Qian;Yuangui Yang
中科院分区：
文献类型：
--
作者：
S. Qian;Yuangui Yang
本文介绍了2002年和2004年FG Hya的光度数据。三个数据集显示了a型、w型和可变奥康奈尔效应之间的交换。由B和V光曲线得到的光度质量比（q = 0.1115 +/- 0.0003）与光谱质量比（q(sp) = 0.112 +/- 0.004）几乎相同。新的光度解显示FG Hya是一个深过接触双星系统（f = 85.6 +/- 1.8%），有一个斑点状的大质量成分。一段时间的调查,基于所有可用的光电或CCD光最低的时候,显示的o c曲线FG Hya可以解释为一个世俗的时期减少和循环变化周期为36.4年和0.0289 d的振幅。通过比较的深度的变化主要与循环周期的变化最小,发现他们两人可能不同相同的周期长度为36.4年,在相同的阶段。光曲线的变化、主成分的斑点化以及周期变化与主最小值深度的关系，都可能表明g0型成分表现为太阳型的磁活动，周期长度为36.4年。长周期的减少可以解释为质量较大的分量向质量较小的分量的质量传递或/和质量从外部拉格朗日点流出造成的角动量损失。
Photometric data on FG Hya obtained in 2002 and 2004 are presented. Three data sets show the exchange between A-type, W-type and the variable O'Connell effects. The photometric mass ratio (q = 0.1115 +/- 0.0003) derived from B and V light curves is almost the same as the spectroscopic mass ratio (q(sp) = 0.112 +/- 0.004). The new photometric solutions reveal that FG Hya is a deep overcontact binary system ( f = 85.6 +/- 1.8 per cent) with a spotted massive component. A period investigation, based on all available photoelectric or CCD times of light minimum, shows that the O-C curve of FG Hya can be explained as a combination of a secular period decrease and a cyclic variation with a period of 36.4 yr and an amplitude of 0.0289 d. By comparing the variation of the depth of the primary minimum with the change of the cyclic period, it is discovered that both of them may vary with the same cycle length of 36.4 yr and in the same phase. The variation of the light curve, the spotted primary component and the connection between the cyclic period change and the depth of the primary minimum, all may suggest that the G0-type component displays solar-type magnetic activity with a 36.4-yr cycle length. The long-time period decrease is interpreted by mass transfer from the more massive component to the less massive one or/and angular momentum loss due to mass outflow from the outer Lagrangian point.