标题： BEAST调查第一部分中B型恒星周围的巨行星种群 显示英文标题

标题： Giant planets population around B stars from the first part of the BEAST survey

摘要： 系外行星形成于围绕恒星的原行星盘，其基本特性（尤其是其范围、组成、质量、温度和寿命）取决于宿主恒星的特性，如其质量和光度。B型恒星是质量最大的恒星之一，它们的原行星盘为系外行星的形成提供了极端条件。本文研究了在天蝎座-半人马座星协中年轻的B型恒星（中位年龄为16 Myr）周围巨行星伴星的频率，这是包含大量B型恒星的最近星协。我们系统地使用高对比度直接成像仪器SPHERE对来自BEAST调查的数据进行搜索，该调查针对的是来自广泛天蝎座-半人马座星协的年轻B型恒星的同质样本。我们在未检测到的情况下推导出准确的检测极限。我们在以前的论文中发现，在42颗恒星周围有两颗亚恒星伴星。这些伴星的质量跨越了约13倍木星质量的氘燃烧极限，但它们相对于宿主恒星的质量比接近木星。我们推导出围绕B型恒星的此类大质量行星伴星的频率为11-5+7%，考虑了调查的敏感性。亚恒星伴星bcen b和mu2sco B的发现发生在仅观察了几颗恒星之后，这引发了围绕B型恒星可能存在大量类木星巨行星的可能性。然而我们的统计分析显示，这种行星在B型恒星和类似年龄的太阳型恒星中的出现率相似，而B型恒星的伴星表现出较低的质量比和较大的半长轴。 显示英文摘要

摘要： Exoplanets form from circumstellar protoplanetary discs whose fundamental properties (notably their extent, composition, mass, temperature and lifetime) depend on the host star properties, such as their mass and luminosity. B-stars are among the most massive stars and their protoplanetary discs test extreme conditions for exoplanet formation. This paper investigates the frequency of giant planet companions around young B-stars (median age of 16 Myr) in the Scorpius-Centaurus association, the closest association containing a large population of B-stars. We systematically search for massive exoplanets with the high-contrast direct imaging instrument SPHERE using the data from the BEAST survey, that targets an homogeneous sample of young B-stars from the wide Sco-Cen association. We derive accurate detection limits in case of non-detections. We found evidence in previous papers for two substellar companions around 42 stars. The masses of these companions are straddling the ~13 Jupiter mass deuterium burning limit but their mass ratio with respect to their host star is close to that of Jupiter. We derive a frequency of such massive planetary mass companions around B stars of 11-5+7%, accounting for the survey sensitivity. The discoveries of substellar companions bcen b and mu2sco B happened after only few stars in the survey had been observed, raising the possibility that massive Jovian planets might be common around B-stars. However our statistical analysis show that the occurrence rate of such planets is similar around B-stars and around solar-type stars of similar age, while B-star companions exhibit low mass ratios and larger semi-major axis.