Evidence for the disintegration of KIC 12557548 b
Evidence for the disintegration of KIC 12557548 b
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KIC 12557548 b 崩解的证据
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
I. Snellen
中科院分区：
文献类型：
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作者：
Matteo Brogi;Christoph U. Keller;M. D. Ovelar;M. Kenworthy;R. Kok;Michiel Min;I. Snellen
上下文开普勒天体KIC 12557548 B是一个奇特的天体。它每隔15.7小时就有一次类似过境的特征，深度在0.2%到1.2%之间变化。Rappaport等人（2012，ApJ，752，1）解释了一个解体的岩石行星的观测结果，该行星有一个由热表面侵蚀产生并不断补充的尘埃云。过境深度的变化是云光学厚度变化的结果。目标。我们的目标是通过对观测到的光变曲线的详细形状进行建模来验证行星解体的情况，从而限制云粒子的属性，以更好地理解这个有趣的物体的性质。方法.我们分析了六个公开的四分之一的原始开普勒数据，对光变曲线进行了相位折叠，并将其拟合到拖尾尘埃云的模型中。颗粒特性的约束进行了研究与光散射代码。结果光变曲线显示出灰尘对光散射和吸收的清晰特征，包括在进入之前与过境深度相关的增亮通量，并通过前向散射解释，以及过境光变曲线形状的不对称性，这很容易通过光学薄灰尘的指数衰减分布再现，典型的颗粒尺寸为0.1 μm。结论.我们的定量分析支持的假设，过境信号的KIC 12557548 B是由于一个可变的尘埃云，最有可能来自一个解体的对象。
Context. The Kepler object KIC 12557548 b is peculiar. It exhibits transit-like features every 15.7 h that vary in depth between 0.2% and 1.2%. Rappaport et al. (2012, ApJ, 752, 1) explain the observations in terms of a disintegrating, rocky planet that has a trailing cloud of dust created and constantly replenished by thermal surface erosion. The variability of the transit depth is then a consequence of changes in the cloud optical depth. Aims. We aim to validate the disintegrating-planet scenario by modeling the detailed shape of the observed light curve, and thereby constrain the cloud particle properties to better understand the nature of this intriguing object. Methods. We analyzed the six publicly-available quarters of raw Kepler data, phase-folded the light curve and fitted it to a model for the trailing dust cloud. Constraints on the particle properties were investigated with a light-scattering code. Results. The light curve exhibits clear signatures of light scattering and absorption by dust, including a brightening in flux just before ingress correlated with the transit depth and explained by forward scattering, and an asymmetry in the transit light curve shape, which is easily reproduced by an exponentially decaying distribution of optically thin dust, with a typical grain size of 0.1 μm. Conclusions. Our quantitative analysis supports the hypothesis that the transit signal of KIC 12557548 b is due to a variable cloud of dust, most likely originating from a disintegrating object.