发表机构
Center for Computational Astrophysics, Flatiron Institute; American Museum of Natural History; Department of Astronomy, The Ohio State University; Center for Cosmology and Astroparticle Physics, The Ohio State University; Department of Astronomy, Columbia University（平顿研究所计算天体物理学中心; 美国自然历史博物馆; 俄亥俄州立大学天文系; 俄亥俄州立大学宇宙学与基本粒子物理中心; 哥伦比亚大学天文系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过同质样本发现M矮星多行星系统比单行星系统金属丰度更低，表明两者起源不同，且动力学演化受金属丰度影响。
AI 中文摘要
目前尚不清楚，在FGK矮星周围，具有一个被探测到凌星行星的系统（“单行星系统”）与具有多个被探测到凌星行星的系统（“多行星系统”）之间，宿主恒星金属丰度是否存在差异。在此，我们发现了强有力的证据表明，对于M矮星而言，这种差异确实存在。我们利用FGK矮星和M矮星化学丰度的同质样本，证明M矮星多行星系统的金属丰度显著低于单行星系统（p = 0.00079），即使我们仅考虑小（<4 R⊕）行星时也是如此（p = 0.0013）。这一结果出现在晚K型到M矮星的过渡区域。我们观察到，随着行星多重性的增加，M矮星多行星系统的金属丰度变得更低。此外，与多行星系统中的行星相比，单行星系统中的行星具有显著更高的偏心率以及更短的轨道周期。我们将这些发现解释为证据，表明M矮星单行星系统经历了相对活跃的动力学演化过程，而单行星系统与多行星系统不同的行星架构源于受金属丰度影响的不同动力学机制。这种情况可能不会发生在FGK系统中，因为其更巨大的原行星盘可能提供足够的行星形成物质，从而引发导致仅形成一个凌星行星的动力学过程，即使宿主恒星金属丰度较低时也是如此。另一种可能性是，FGK矮星周围的多行星系统不那么紧凑，因为它们形成于更大的盘中，这常常导致它们在凌星数据中被观测为单行星系统。
英文摘要
It is unclear if host star metallicities differ between systems with one detected transiting planet ("singles") or multiple detected transiting planets ("multis") around FGK dwarfs. Here, we find strong evidence that they do for M dwarfs. We use a homogeneous sample of FGK and M dwarf chemical abundances to demonstrate that M dwarf multis are significantly more metal-poor than singles ($p$ = 0.00079), even when we only consider small (<4 $R_{\oplus}$) planets ($p$ = 0.0013). This result emerges at the late-K to M dwarf transition. We observe that M dwarf multis become more metal-poor as a function of increasing planet multiplicity. Additionally, planets in singles have significantly higher eccentricities and shorter orbital periods compared to planets in multis. We interpret these findings as evidence that M dwarf singles lead relatively active dynamical lives, and the different planetary architectures of singles and multis arise from distinct dynamics influenced by metallicity. This may not occur in FGK systems because their more massive protoplanetary disks may supply enough planet-forming material to instigate dynamics that lead to only one transiting planet, even when the host star metallicity is low. Another possibility is that multis are less compact around FGK dwarfs because they form from larger disks, which may often cause them to be observed as singles in transit data.
Comments19 pages, under review at AAS Journals
