Photometric study of the short-period RS Canum Venaticorum binary RT Andromedae
Photometric study of the short-period RS Canum Venaticorum binary RT Andromedae
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DOI：
10.1051/0004-6361:20066767
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发表时间：
2007-08
影响因子：
6.5
通讯作者：
Li-yun Zhang;S. Gu
中科院分区：
文献类型：
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作者：
Li-yun Zhang;S. Gu
上下文对冷星的长期光度观测可以揭示恒星活动区的演化和活动周期。此外，研究恒星活动为理解恒星发电机提供了机会，也为恒星发电机理论提供了有价值的约束。目标。我们分析了我们的观测数据，并讨论了光变曲线的变化，由于恒星黑子在短期和长期的时间尺度，特别是短期的变化。同时，我们也积累了一些有关活动区演化和活动旋回的研究成果。方法.利用Wilson-Devinney程序对光变曲线进行分析，得到了系统的光度解，并导出了星斑参数。利用相弥散最小化方法，我们推断了RT And的活动周期。结果在2004年，在再现RT And的光变曲线失真方面，两个光斑位于主光源上的情况最为成功。虽然1999年和2005年的光变曲线没有足够的相位覆盖，但我们仍然可以在2004年光度解的基础上，用光斑模型成功地解释它们的光变曲线变化。对比1999年、2004年和2005年的光变曲线，发现光变曲线畸变在短、长时间尺度上都发生了变化，特别是在2个月时间尺度上的次极小值附近发生了显著变化。对270度附近带内点的经度分析表明，RT And的活动周期可能为6.69 +/-0.80年。
Context. Long-term photometric observations of cool stars can reveal the evolution and activity cycles of the stellar active region. Furthermore, studying the stellar activity provides opportunities for understanding of stellar dynamo and valuable constraints for stellar dynamo theory. Aims. We analyze our observational data and discuss light-curve variability due to starspots on both a short and long time scale, especially the short-term variation. At the same time, we accumulate some results from the literature to discuss active-region evolution and activity cycles. Methods. By analyzing the light curves using the Wilson-Devinney program, the photometric solution of the system is obtained and the starspot parameters are also derived. Using the phase-dispersion minimization method, we infer the activity cycle of RT And. Results. The case of two spots being on the primary is most successful in reproducing the light curve distortion of RT And in 2004. Although the light curves in 1999 and 2005 do not have sufficient phase coverage, we still could use the spot model to explain their light-curve variation successfully based on the photometric solution in 2004. Comparing the light curves of 1999, 2004, and 2005, the light curve distortion changes on both short and long time scales, especially the significant variation around the secondary minimum on a time scale of two months. Analysis of the longitude of spots within the belt around 270 degrees suggests that the activity cycle of RT And may be 6.69 +/- 0.80 years.