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.

木星行星的形成已被证明与宿主恒星的金属丰度密切相关，这被认为是盘固体的代表。在观测方面，以前的工作表明，木星行星优先围绕具有太阳和超太阳金属丰度的恒星形成。鉴于这些发现，在缺乏金属的环境中形成行星具有挑战性，特别是对于被认为是通过依赖金属含量的核心吸积形成的热木星。尽管之前的研究已经对贫金属恒星周围的热木星进行了行星搜索，但由于样本量小，这些研究受到了限制，这是由于缺乏高质量数据使得热木星在贫金属区域内的出现变得困难约束到现在。我们使用 TESS 观测到的大量晕星样本来限制热木星出现在贫金属区 (-2.0 ≤ [Fe/H] ≤ -0.6) 的上限。对热木星的出现设置最严格的上限，我们发现平均 1对于半径 0.8-2 R _木星和周期 0.5-10 天，σ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，低于该金属丰度就不会形成行星。