The light and period changes of RT Andromedae
The light and period changes of RT Andromedae
复制标题
DOI：
10.1051/0004-6361:20011357
复制
发表时间：
2001-12
影响因子：
6.5
通讯作者：
A. Erdem;O. Demircan;M. Güre
中科院分区：
文献类型：
--
作者：
A. Erdem;O. Demircan;M. Güre
利用现有的光度观测资料，研究了RT和长期轨道周期变化和光照变化的性质。由所有可能的日食最小时刻组成的（O{C）图可以是叠加在抛物线形式上的准正弦形式，也可以是长周期正弦形式。其振幅为0.002天，周期为65年的准正弦形式可能是由于系统轨道周期的周期性磁活动调制所致。在这种情况下，Applegate的理论（Applegate 1992）预测系统主要成分的平均地下磁场为3kg。抛物线形式对应于由系统质量损失引起的长期周期减少约3 10 9 m yr 1，振幅为0.02天，周期为105年的长周期正弦形式对应于由系统中看不见的第三颗恒星引起的光时效应引起的长期周期变化。据估计，未观测到的第三颗恒星应该是一颗低质量（小于0:6 m）且亮度较弱（比RT和系统暗5:m）的恒星，几乎不可能被探测到。未来的数据将增加关于长期（O{C）变化性质的信息。发现系统的长期亮度变化是不规则的，与轨道周期变化没有相关性。
The nature of the long-term orbital period variation and the light level variation of RT And was studied based on all available photometric observations. The (O{C) diagram formed by all available times of eclipse minima could be either of a quasi-sinusoidal form superimposed on a parabolic form, or a long period sinusoidal form. The quasi-sinusoidal form with an amplitude of 0.002 days and a period of 65 years could be due to a cyclic magnetic activity modulation on the orbital period of the system. Applegate's theory (Applegate 1992), in this case, predicts an3 kG mean subsurface magnetic eld for the primary component of the system. The parabolic form corresponds to a secular period decrease of about 3 10 9 m yr 1 caused by mass loss from the system, and the long-period sinusoidal form with an amplitude of 0.02 days and a period of 105 years corresponds to a secular period change caused by the light-time eect due to an unseen third star in the system. It was estimated that the unseen third star should be a low mass (lower than 0:6 m) and faint (5: m fainter than the system RT And) star, whose detection is almost impossible. Future data will add information on the nature of the secular (O{C) variation. Secular light level variation of the system was found to be irregular and no correlation was detected with the orbital period variation.