论文标题
对传播系外行星宿主星的多重研究。 I.用VLT/Sphere进行高对比度成像
A multiplicity study of transiting exoplanet host stars. I. High-contrast imaging with VLT/SPHERE
论文作者
论文摘要
我们研究了宿主恒星与已知的过晶超极性行星的多样性，以测试有关热木星形成机理的竞争理论。我们使用VLT/Sphere/Irdis观察到45个系外行星宿主星来寻找潜在的伴侣。对于每个确定的候选伴侣，我们确定了它通过对宿主周围的合成恒星种群进行共同的适当运动检查和建模而在其主机上重力结合的概率。我们在K2-38，WASP-72，WASP-80，WASP-87，WASP-88，WASP-108，WASP-108，WASP-118，WASP-120，WASP-120，WASP-122，WASP-122，WASP123，WASP123，WASP-130，WASP-130，WASP-131，WASP-131，WASP-131，WASP-131和WASP-137附近检测到了新的候选同伴。在$ 0.124'\ pm0.007'''$和0.189''\ pm0.003''$ 0.124''\ pm0.007'''$ 0.124''\ pm0.007''$周围的$ 0.124''\ pm0.007''$周围检测到最接近的候选人。测量的$ k $频段对比表明，这些是$ 0.35 \ pm0.02 \，m _ {\ odot} $的恒星伴侣，分别分别分别分别。包括在其他13个系统中重新检测和确认以前已知的同伴，我们得出了$ 55.4^{+5.9} _ { - 9.4} \，\％$的多重分数。对于我们目标中40个热木星主机星的代表性子样本，派生的多重速率为$ 54.8^{+6.3} _ { - 9.9} \，\％$。我们的数据尚未确认具有偏心行星同伴的系统优选是多个系统的一部分。平均而言，我们以0.5''的角度分离达到了$ 8.5 \ pm0.9 $ mag的幅度对比度。这允许将几乎所有观察到的系统的质量大于$ 0.08 $ m $ _ \ odot $排除其他恒星伴侣；在最接近和最年轻的系统附近，这种敏感性是在小至10 au的物理分离下实现的。提出的研究表明，球体是检测和表征系托宿主星的亲密伴侣的理想工具。
We study the multiplicity of host stars to known transiting extra-solar planets to test competing theories on the formation mechanisms of hot Jupiters. We observed 45 exoplanet host stars using VLT/SPHERE/IRDIS to search for potential companions. For each identified candidate companion we determined the probability that it is gravitationally bound to its host by performing common proper motion checks and modelling of synthetic stellar populations around the host. We detected new candidate companions around K2-38, WASP-72, WASP-80, WASP-87, WASP-88, WASP-108, WASP-118, WASP-120, WASP-122, WASP123, WASP-130, WASP-131 and WASP-137. The closest candidates were detected at separations of $0.124''\pm0.007''$ and $0.189''\pm0.003''$ around WASP-108 and WASP-131; the measured $K$ band contrasts indicate that these are stellar companions of $0.35\pm0.02\,M_{\odot}$ and $0.62^{+0.05}_{-0.04}\,M_{\odot}$, respectively. Including the re-detection and confirmation of previously known companions in 13 other systems we derived a multiplicity fraction of $55.4^{+5.9}_{-9.4}\,\%$. For the representative sub-sample of 40 hot Jupiter host stars among our targets, the derived multiplicity rate is $54.8^{+6.3}_{-9.9}\,\%$. Our data do not confirm any trend that systems with eccentric planetary companions are preferably part of multiple systems. On average, we reached a magnitude contrast of $8.5\pm0.9$ mag at an angular separation of 0.5''. This allows to exclude additional stellar companions with masses larger than $0.08$ M$_\odot$ for almost all observed systems; around the closest and youngest systems this sensitivity is achieved at physical separations as small as 10 au. The presented study shows that SPHERE is an ideal instrument to detect and characterize close companions to exoplanetary host stars.
