颠倒：GJ3090 b——NIRPS 探测到的首颗围绕M矮星的逆行系外行星
Upside down: GJ3090 b the first retrograde exoplanet around an M dwarf detected with NIRPS
- Université de Genève（日内瓦大学）
- Queen Mary University of London（伦敦玛丽女王大学）
- Université de Montréal（蒙特利尔大学）
- Universidade Federal do Rio Grande do Norte（北里奥格兰德联邦大学）
- Instituto de Astrofísica de Canarias (IAC)（加那利天体物理研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过NIRPS和HARPS观测，利用RM反转技术发现亚海王星GJ3090 b是首颗围绕M矮星的逆行行星，其三维倾角为136度，并推测其源于原行星盘错位及盘驱动迁移。
AI中文摘要：
恒星自转轴与行星轨道平面之间的夹角可以为行星系统的形成和动力学演化提供关键见解。特别是，在多行星系统中进行这种测量，可用于进一步区分不同的竞争性迁移情景。我们展示了利用NIRPS和HARPS对亚海王星GJ3090 b进行的六次凌星观测。GJ3090 b是已确认的多行星系统中围绕一颗M矮星（M2）运行的内侧行星。利用高光谱分辨率和时间分辨率的 spectroscopic 观测，我们分析了GJ3090 b引起的Rossiter-McLaughlin（RM）效应，以确定其轨道倾角。通过RM反转技术，我们发现该行星处于逆行轨道，其三维倾角为 $\psi = 136^{+24}_{-18}\\,\mathrm{deg}$。我们没有发现大质量外侧行星或宽距恒星伴星的证据，这不利于涉及大质量天体引力扰动的情景，反而指向原行星盘的原始错位。我们的结果确立了GJ3090 b是首颗围绕M矮星发现的逆行轨道行星，也是首个没有已知大质量伴星的高度错位的已确认多行星系统。我们进一步提出GJ3090周围晚期次级盘吸积，其中盘预计不会与恒星自转轴对齐，随后由盘驱动的迁移是解释所观测到的架构的最可能机制。这项工作也展示了RM反转技术应用于近红外数据时，能够探测M矮星周围最小的行星的轨道架构，而这些行星此前大多难以观测。
英文摘要：
The angle between stellar spin axis and planetary orbital plane can provide key insights into the formation and dynamical evolution of planetary systems. In particular, this measurement in multi-planet systems can be used to further discriminate between different competing migration scenarios. We present six transit observations of the sub-Neptune GJ3090 b obtained with NIRPS and HARPS. GJ3090 b is the inner planet of a confirmed multi-planet system orbiting an M dwarf (M2). Using high spectral resolution and high temporal cadence spectroscopic observations, we analyzed the Rossiter-McLaughlin (RM) effect induced by GJ3090 b to determine its orbital obliquity. Through the RM revolutions technique, we find that the planet is on a retrograde orbit with a derived 3D obliquity of $ψ= 136^{+24}_{-18}\,\mathrm{deg}$. We find no evidence of massive outer planetary or wide stellar binary companions, which disfavors scenarios involving gravitational perturbations from a massive body and instead points toward a primordial misalignment of the protoplanetary disk. Our results establish GJ3090 b as the first planet on a retrograde orbit discovered around an M dwarf and the first highly misaligned confirmed multi-planet system without a known massive companion. We further propose late secondary disk accretion around GJ3090, in which the disk is not expected to be aligned with the stellar spin axis, followed by disk-driven migration as the most likely mechanisms to explain the observed architecture. This work also illustrates the capability of the RM revolutions technique when applied to near-infrared data to probe orbital architectures of the smallest planets around M dwarfs that have remained mostly inaccessible.
