arXiv 2009.092762020-09-22astro-ph.EPastro-ph.SR

用高斯过程恒星活动模型估算$β$如画行星系的动力学质量

Dynamical Mass Estimates of the $β$ Pictoris Planetary System Through Gaussian Process Stellar Activity Modelling

Thomas Vandal, Julien Rameau, René Doyon

备注：: 25 pages, 18 figures, Accepted to AJ, Typos Corrected
发表信息：: 2020 AJ 160 243
DOI：: 10.3847/1538-3881/abba30

摘要：

近15年的径向速度（RV）监测和直接成像使两颗巨大的行星绕着年轻的附近恒星$β$ Picture被发现。恒星的$δ$盾牌脉动，压倒性的行星信号，需要小心抑制。在这项工作中，我们独立地重新审视RV数据的分析，采用与文献中不同的方法来模拟恒星的活动。我们发现，高斯过程（GP）与随机驱动的阻尼谐振子内核可以模拟$δ$盾牌脉动。它提供了与参数模型类似的结果，但具有更简单的框架，仅使用3个超参数。它还可以对之前分析中排除的采样较差的RV数据进行建模，从而将RV基线延长近五年。总而言之，两颗行星的轨道和质量只能从RV约束，这在参数建模中是不可能的。为了更准确地表征系统，我们还对所有可用的相对天体测量和RV数据进行了联合拟合。我们对$β$ Pic b的轨道解支持低离心率的$0.029^{+0.061}_{-0.024}$和相对短的周期$21.1^{+2.0}_{-0.8}$ yr。$β$ Pic c的轨道与$0.206^{+0.074}_{-0.063}$偏心，周期为$3.36\pm0.03$年。假设共面性，我们发现$β$ Pic b和c的$11.7\pm1.4$和$8.5\pm0.5$ M $_{Jup}$的模型独立质量。$β$ Pic b的质量与最热的开始进化模型一致，年龄为$25\pm3$ Myr。$β$ Pic c的直接方向将在同时期系统中提供第二次校准测量。

英文摘要：

Nearly 15 years of radial velocity (RV) monitoring and direct imaging enabled the detection of two giant planets orbiting the young, nearby star $β$ Pictoris. The $δ$ Scuti pulsations of the star, overwhelming planetary signals, need to be carefully suppressed. In this work, we independently revisit the analysis of the RV data following a different approach than in the literature to model the activity of the star. We show that a Gaussian Process (GP) with a stochastically driven damped harmonic oscillator kernel can model the $δ$ Scuti pulsations. It provides similar results as parametric models but with a simpler framework, using only 3 hyperparameters. It also enables to model poorly sampled RV data, that were excluded from previous analysis, hence extending the RV baseline by nearly five years. Altogether, the orbit and the mass of both planets can be constrained from RV only, which was not possible with the parametric modelling. To characterize the system more accurately, we also perform a joint fit of all available relative astrometry and RV data. Our orbital solutions for $β$ Pic b favour a low eccentricity of $0.029^{+0.061}_{-0.024}$ and a relatively short period of $21.1^{+2.0}_{-0.8}$ yr. The orbit of $β$ Pic c is eccentric with $0.206^{+0.074}_{-0.063}$ with a period of $3.36\pm0.03$ yr. We find model-independent masses of $11.7\pm1.4$ and $8.5\pm0.5$ M$_{Jup}$ for $β$ Pic b and c, respectively, assuming coplanarity. The mass of $β$ Pic b is consistent with the hottest start evolutionary models, at an age of $25\pm3$ Myr. A direct direction of $β$ Pic c would provide a second calibration measurement in a coeval system.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文