论文标题
通过高斯工艺恒星活动建模的$β$ Pictoris行星系统的动态质量估计
Dynamical Mass Estimates of the $β$ Pictoris Planetary System Through Gaussian Process Stellar Activity Modelling
论文作者
论文摘要
将近15年的径向速度（RV）监测和直接成像使两个巨型行星可检测到附近的年轻恒星$β$ pictoris的巨型行星。恒星的$δ$ Scuti脉动，压倒性的行星信号需要仔细抑制。在这项工作中，我们独立地重新审视了与文献不同的方法对RV数据的分析，以模拟恒星的活动。我们表明，具有随机驱动的阻尼谐波振荡器内核的高斯工艺（GP）可以对$δ$ scuti脉动进行建模。它提供了与参数模型相似的结果，但仅使用3个超参数使用更简单的框架。它还可以模拟先前分析中排除的较差的RV数据，从而将RV基线延长了近五年。总体而言，两个行星的轨道和质量只能从RV限制，这是参数建模是不可能的。为了更准确地表征系统，我们还执行所有可用的相对天体和RV数据的关节拟合。我们针对$β$ pic b的轨道解决方案偏爱$ 0.029^{+0.061} _ { - 0.024} $的低偏心度，相对较短的$ 21.1^{+2.0} _ { - 0.8} $ yr。 $β$ pic c的轨道偏心，$ 0.206^{+0.074} _ { - 0.063} $，周期为$ 3.36 \ pm0.03 $ yr。我们发现，假设$β$ pic b和c，我们发现$ 11.7 \ pm1.4 $和$ 8.5 \ pm0.5 $ m $ _ {jup} $，假设Coplanarity分别为$β$ pic b和c。 $β$ pic b的质量与最热门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系统中提供第二个校准测量。
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.
