Spot modelling of periodic weak-line T Tauri stars observed by CoRoT in NGC 2264
Spot modelling of periodic weak-line T Tauri stars observed by CoRoT in NGC 2264
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DOI：
10.1051/0004-6361/201628382
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发表时间：
2016-06
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影响因子：
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通讯作者：
Antonino Francesco Lanza;E. Flaccomio;S. Messina;G. Micela;I. Pagano;G. Leto
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作者：
Antonino Francesco Lanza;E. Flaccomio;S. Messina;G. Micela;I. Pagano;G. Leto
在一个协调的多波长观测项目框架内，CoRoT空间望远镜以前所未有的连续性和精确度提供了属于NGC 2264恒星形成区的金牛座T星的光变曲线。我们进行现场建模的光学光变曲线的五个弱线金牛座T星的变化是由星点。我们应用两个点和不断发展的单点模型的框架下的贝叶斯蒙特卡罗马尔可夫链方法来推导的后验分布的星点参数和倾角的星星旋转轴。我们专注于旋转周期的斑点，可以提供证据，在这些恒星的差异旋转。我们发现有意义的结果的情况下，三颗恒星的倾角高于50度和光变曲线振幅的缓慢变化。这两颗恒星自转周期的相对差值在0.02到0.05之间，比用多普勒成像技术在类似恒星中发现的自转差幅值大3到10倍。我们的结论是，内在的恒星黑子的演变，虽然非常缓慢，有显着的影响，通过我们的现场建模方法的差分旋转的确定。我们估计典型的时间尺度约20和50之间的旋转周期在我们的恒星的星斑图案的演变。
The space telescope CoRoT has provided light curves of T Tauri stars belonging to the star-forming region of NGC 2264 with unprecedented continuity and precision in the framework of a coordinated multi-wavelength observational project. We perform spot modelling of the optical light curves of five weak-line T Tauri stars whose variability is dominated by starspots. We apply two-spot and evolving single spot models in the framework of a Bayesian Monte Carlo Markov Chain approach to derive the a posteriori distribution of the starspot parameters and the inclination of the star rotation axis. We focus on the rotation periods of the spots that can provide evidence for differential rotation in those stars. We find meaningful results in the case of three stars with an inclination higher than 50 deg and a slow variation of the light curve amplitude. The relative difference of the spot rotation periods ranges from 0.02 to 0.05 that is 3-10 times larger than the amplitude of the differential rotation found in similar stars with Doppler imaging techniques. We conclude that the intrinsic starspot evolution, although very slow, has a significant impact on the determination of the differential rotation by means of our spot modelling approach. We estimate typical timescales for the evolution of the starspot pattern between about 20 and 50 rotation periods in our stars.