Accretion dynamics and disk evolution in NGC 2264: a study based on CoRoT photometric observations
Accretion dynamics and disk evolution in NGC 2264: a study based on CoRoT photometric observations
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NGC 2264 中的吸积动力学和盘演化：基于 CoRoT 光度观测的研究
DOI：
10.1051/0004-6361/201014184
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发表时间：
2010
影响因子：
6.5
通讯作者：
Alencar S
中科院分区：
文献类型：
--
作者：
Alencar S
2008年3月，CoRoT卫星以前所未有的光度精度对年轻星团NGC 2264进行了23天的不间断观测。我们提出的第一个结果，我们的分析属于集群的吸积人口所观察到的CoRoT。AimsWe搜索可能的光变曲线的变化相同的性质，观察到的经典金牛座T星星AA头，这是由于一个磁控内盘翘曲。内部翘曲动力学应该是直接与恒星磁场和内部磁盘regions.MethodsWe之间的相互作用分析了CoRoT光变曲线的83个以前已知的经典金牛座T星属于NGC 2264分类他们根据他们的光变曲线形态。我们还研究了CoRoT的光变曲线形态作为一个函数的斯皮策为基础的分类的星盘system.ResultsThe分类的基础上推导出的CoRoT的光变曲线形态同意非常好与thespitzerIRAC为基础的分类系统。类AA Tau光变曲线的百分比随着内盘的消散而减少，从厚内盘系统的40%±10%减少到贫血盘系统的36%±16%和裸光球系统的零。事实上，91%±29%的CTTS与裸露的光球表现出纯粹的斑点状的变化，而只有18%±7%的厚盘系统这样做，大概是那些看到在低倾角，从而免费的可变obscurations.ConclusionsAA Tau光变曲线被发现是相当常见的，与一个频率至少为30至40%的年轻恒星与内部尘埃盘。光变曲线的时间演化表明，位于正转半径附近的内部盘弯曲的结构，负责遮蔽事件，在几个（~1-3）旋转周期的时间尺度上变化。这可能反映了恒星-磁盘磁层相互作用的高度动态性质。
ContextThe young cluster NGC 2264 was observed with the CoRoT satellite for 23 days uninterruptedly in March 2008 with unprecedented photometric accuracy. We present the first results of our analysis of the accreting population belonging to the cluster as observed by CoRoT.AimsWe search for possible light curve variability of the same nature as that observed in the classical T Tauri star AA Tau, which was attributed to a magnetically controlled inner disk warp. The inner warp dynamics is supposed to be directly associated with the interaction between the stellar magnetic field and the inner disk region.MethodsWe analyzed the CoRoT light curves of 83 previously known classical T Tauri stars that belong to NGC 2264 classifying them according to their light-curve morphology. We also studied the CoRoT light-curve morphology as a function of aSpitzer-based classification of the star-disk systems.ResultsThe classification derived on the basis of the CoRoT light-curve morphology agrees very well with theSpitzerIRAC-based classification of the systems. The percentage of AA Tau-like light curves decreases as the inner disk dissipates, from 40%±10% in systems with thick inner disks to 36%±16% in systems with anemic disks and zero in naked photosphere systems. Indeed, 91%±29% of the CTTS with naked photospheres exhibit pure spot-like variability, while only 18%±7% of the thick disk systems do so, presumably those seen at low inclination and thus free of variable obscuration.ConclusionsAA Tau-like light curves are found to be fairly common, with a frequency of at least ~30 to 40% in young stars with inner dusty disks. The temporal evolution of the light curves indicates that the structure of the inner disk warp, located close to the corotation radius and responsible for the obscuration episodes, varies over a timescale of a few (~1–3) rotational periods. This probably reflects the highly dynamical nature of the star-disk magnetospheric interaction.