Constraining disk evolution prescriptions of planet population synthesis models with observed disk masses and accretion rates
Constraining disk evolution prescriptions of planet population synthesis models with observed disk masses and accretion rates
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DOI：
10.1051/0004-6361/201936488
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发表时间：
2019-09
影响因子：
6.5
通讯作者：
C. Manara;C. Mordasini;L. Testi;J. Williams;A. Miotello;G. Lodato;A. Emsenhuber
中科院分区：
文献类型：
--
作者：
C. Manara;C. Mordasini;L. Testi;J. Williams;A. Miotello;G. Lodato;A. Emsenhuber
虽然行星通常在主序恒星周围被发现，但导致其形成的过程仍然远未被了解。当前的行星种群合成模型旨在描述从原行星盘阶段到观察到系外行星的时间的行星形成过程，依赖于行星形成和演化的原行星盘的基本特性的规定。最近在测量年轻恒星物体的大样本中的盘质量和盘-恒星相互作用特性（即质量吸积率）方面的进展需要对模型和数据进行更仔细的比较。我们通过观察模型和当前可用数据中的质量吸积率和盘质量之间的关系，对行星合成人口模型所做的假设进行了初步的关键评估。我们发现当前使用的圆盘模型预测的质量吸积率与测量值一致，但值的分布比观察到的要低得多。这种差异主要是因为模型的粘性时间尺度分布比重现观察结果所需的要小。相对于典型圆盘的观测，我们还发现在巨行星形成的模型中存在过多的弱吸积盘。我们认为，要么现实中形成的巨行星较少，要么行星吸积的处方预测行星上的吸积过高。最后，对具有大空腔的过渡盘的特性的比较证实，在许多此类物体中，观察到的吸积率高于模型预测的吸积率。另一方面，PDS70（一个在空腔中检测到两颗巨行星的过渡盘）显示出质量吸积率与模型预测非常一致。
While planets are commonly discovered around main-sequence stars, the processes leading to their formation are still far from being understood. Current planet population synthesis models, which aim to describe the planet formation process from the protoplanetary disk phase to the time exoplanets are observed, rely on prescriptions for the underlying properties of protoplanetary disks where planets form and evolve. The recent development in measuring disk masses and disk-star interaction properties, i.e., mass accretion rates, in large samples of young stellar objects demand a more careful comparison between the models and the data. We performed an initial critical assessment of the assumptions made by planet synthesis population models by looking at the relation between mass accretion rates and disk masses in the models and in the currently available data. We find that the currently used disk models predict mass accretion rate in line with what is measured, but with a much lower spread of values than observed. This difference is mainly because the models have a smaller spread of viscous timescales than what is needed to reproduce the observations. We also find an overabundance of weakly accreting disks in the models where giant planets have formed with respect to observations of typical disks. We suggest that either fewer giant planets have formed in reality or that the prescription for planet accretion predicts accretion on the planets that is too high. Finally, the comparison of the properties of transition disks with large cavities confirms that in many of these objects the observed accretion rates are higher than those predicted by the models. On the other hand, PDS70, a transition disk with two detected giant planets in the cavity, shows mass accretion rates well in line with model predictions.