Searching For Transiting Planets Around Halo Stars. ii. Constraining the Occurrence Rate of Hot Jupiters
Searching For Transiting Planets Around Halo Stars. ii. Constraining the Occurrence Rate of Hot Jupiters
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DOI：
10.3847/1538-3881/ac0e2d
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发表时间：
2021-06
期刊：
影响因子：
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通讯作者：
Kiersten M. Boley;Ji Wang;J. Zinn;K. Collins;K. Collins;T. Gan;Ting S. Li
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作者：
Kiersten M. Boley;Ji Wang;J. Zinn;K. Collins;K. Collins;T. Gan;Ting S. Li
木星行星的形成已被证明与主星金属丰度密切相关，这被认为是盘固体的代表。通过观察，之前的研究表明，木星行星优先在具有太阳和超太阳金属丰度的恒星周围形成。鉴于这些发现，在贫金属环境中形成行星具有挑战性，特别是对于被认为是通过金属丰度相关的核心吸积形成的热木星而言。尽管之前的研究已经在贫金属恒星周围进行了行星搜索，但由于样本量较小，这些研究受到了限制，这是由于缺乏高质量的数据，使得热木星在贫金属区域内的出现迄今为止很难限制。我们使用 TESS 观测到的晕星的大样本来限制贫金属区域内热木星出现的上限 (−2.0 ≤ [Fe/H] ≤ -0.6)。对热木星的出现设定了最严格的上限，我们发现对于半径为 0.8–2 R 的木星和周期为 0.5–10 天的平均 1σ 上限为 0.18%。这一结果与之前的预测一致，表明存在一定的金属丰度，低于该金属丰度就无法形成行星。
Jovian planet formation has been shown to be strongly correlated with host-star metallicity, which is thought to be a proxy for disk solids. Observationally, previous works have indicated that Jovian planets preferentially form around stars with solar and supersolar metallicities. Given these findings, it is challenging to form planets within metal-poor environments, particularly for hot Jupiters that are thought to form via metallicity-dependent core accretion. Although previous studies have conducted planet searches for hot Jupiters around metal-poor stars, they have been limited due to small sample sizes, which are a result of a lack of high-quality data making hot-Jupiter occurrence within the metal-poor regime difficult to constrain until now. We use a large sample of halo stars observed by TESS to constrain the upper limit of hot-Jupiter occurrence within the metal-poor regime (−2.0 ≤ [Fe/H] ≤ −0.6). Placing the most stringent upper limit on hot-Jupiter occurrence, we find the mean 1σ upper limit to be 0.18% for radii 0.8–2 R Jupiter and periods 0.5–10 days. This result is consistent with previous predictions indicating that there exists a certain metallicity below which no planets can form.