A POSSIBLE DETECTION OF OCCULTATION BY A PROTO-PLANETARY CLUMP IN GM Cephei
A POSSIBLE DETECTION OF OCCULTATION BY A PROTO-PLANETARY CLUMP IN GM Cephei
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DOI：
10.1088/0004-637x/751/2/118
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发表时间：
2012-03
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通讯作者：
Wen-Ping Chen;S. C. Hu;R. Errmann;C. Adam;S. Baar;A. Berndt;L. Bukowiecki;Dinko Dimitrov;T. Eisenbeiss;S. Fiedler;C. Ginski;C. Gräfe;C. Gräfe;J. Guo;M. Hohle;H. Y. Hsiao;R. Janulis;M. Kitze;H. C. Lin;C. S. Lin;G. Maciejewski;G. Maciejewski;C. Marka;L. Marschall;M. Moualla;M. Mugrauer;R. Neuhäuser;T. Pribulla;T. Pribulla;S. Raetz;T. Röll;E. Schmidt;J. Schmidt;T. Schmidt;M. Seeliger;L. Trepl;C. Briceño;R. Chini;Eric L. N. Jensen;E. H. Nikogossian;A. K. Pandey;J. Sperauskas;Hiromitsu Takahashi;F. M. Walter;Zhenyu Wu;Xin Zhou
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作者：
Wen-Ping Chen;S. C. Hu;R. Errmann;C. Adam;S. Baar;A. Berndt;L. Bukowiecki;Dinko Dimitrov;T. Eisenbeiss;S. Fiedler;C. Ginski;C. Gräfe;C. Gräfe;J. Guo;M. Hohle;H. Y. Hsiao;R. Janulis;M. Kitze;H. C. Lin;C. S. Lin;G. Maciejewski;G. Maciejewski;C. Marka;L. Marschall;M. Moualla;M. Mugrauer;R. Neuhäuser;T. Pribulla;T. Pribulla;S. Raetz;T. Röll;E. Schmidt;J. Schmidt;T. Schmidt;M. Seeliger;L. Trepl;C. Briceño;R. Chini;Eric L. N. Jensen;E. H. Nikogossian;A. K. Pandey;J. Sperauskas;Hiromitsu Takahashi;F. M. Walter;Zhenyu Wu;Xin Zhou
在年轻的（~ 4myr）疏散星团Trumpler 37中，造父星GM （GM Cep）被认为是一个突变变量，并且有一个非常活跃的吸积星周盘。我们在2009-2011年的监测观测显示，这颗恒星出现了零星的耀斑事件，每次亮度都在0.5等左右，持续数天。这些变亮的事件，与颜色变蓝有关，应该是由于增加的吸积活动。此外，这颗恒星还经历了持续一个月的亮度下降约1等的过程，在此期间，恒星变得更暗，颜色也变得更蓝。这种亮度下降似乎有一年的重复时间尺度，正如我们的数据和GM Cep超过一个世纪的光度行为所证明的那样。在连续的下降之间，这颗恒星逐渐变亮了大约1等，在峰值亮度时变成了蓝色。我们认为，这种下降是由于轨道尘埃浓度对中心恒星的遮挡造成的。因此，猎户座UX型活动在GM Cep中体现了年轻星周盘在颗粒凝聚和星子形成之间过渡的不均匀性过程。
GM Cephei (GM Cep), in the young (∼4 Myr) open cluster Trumpler 37, has been known to be an abrupt variable and to have a circumstellar disk with a very active accretion. Our monitoring observations in 2009–2011 revealed that the star showed sporadic flare events, each with a brightening of ≲ 0.5 mag lasting for days. These brightening events, associated with a color change toward blue, should originate from increased accretion activity. Moreover, the star also underwent a brightness drop of ∼1 mag lasting for about a month, during which time the star became bluer when fainter. Such brightness drops seem to have a recurrence timescale of a year, as evidenced in our data and the photometric behavior of GM Cep over a century. Between consecutive drops, the star brightened gradually by about 1 mag and became blue at peak luminosity. We propose that the drop is caused by the obscuration of the central star by an orbiting dust concentration. The UX Orionis type of activity in GM Cep therefore exemplifies the disk inhomogeneity process in transition between the grain coagulation and the planetesimal formation in a young circumstellar disk.