近日，美国德克萨斯大学Lauren I. Biddle团队揭示了三分之一的类太阳恒星诞生时，其行星形成盘没有对齐。该研究于2025年8月6日发表在《自然》杂志上。

系外行星被组织成一系列广泛的轨道构型，这些构型反映了它们经过数十亿年引力相互作用的动态过程而形成。这段历史被编码在行星系统的角动量结构中——中心恒星的旋转特性和行星的轨道几何之间的关系。主要观测到的是恒星旋转轴和行星轨道平面之间的对齐（或不对齐），称为恒星倾角。

对靠近主星的巨行星进行了数百次自旋轨道约束测量，其中许多发现了轨道失调的行星。已经出现的一个主要问题是，恒星的倾角是否主要源于与同一系统中其他行星或遥远恒星的引力相互作用，或者它是否是在恒星形成过程中留下的“原始”印记。

研究组对年轻的、孤立的类太阳恒星的自转轴和它们的原行星盘外区域的方向之间的原始倾角进行了全面评估。大多数系统与角动量排列一致，但大约三分之一的孤立年轻系统表现出原始失调。这表明，在年龄较大的行星系统中发现的一些倾角——包括太阳与太阳系中行星的适度错位——可能源于它们形成的初始条件。

附：英文原文

Title: One-third of Sun-like stars are born with misaligned planet-forming disks

Author: Biddle, Lauren I., Bowler, Brendan P., Morgan, Marvin, Tran, Quang H., Wu, Ya-Lin

Issue&Volume: 2025-08-06

Abstract: Exoplanets are organized in a broad array of orbital configurations1,2 that reflect their formation along with billions of years of dynamical processing through gravitational interactions3. This history is encoded in the angular momentum architecture of planetary systems—the relation between the rotational properties of the central star and the orbital geometry of planets. A primary observable is the alignment (or misalignment) between the rotational axis of the star and the orbital plane of its planets, known as stellar obliquity. Hundreds of spin–orbit constraints have been measured for giant planets close to their host stars4, many of which have revealed planets on misaligned orbits. A leading question that has emerged is whether stellar obliquity originates primarily from gravitational interactions with other planets or distant stars in the same system, or if it is ‘primordial’—imprinted during the star-formation process. Here we present a comprehensive assessment of primordial obliquities between the spin axes of young, isolated Sun-like stars and the orientation of the outer regions of their protoplanetary disks. Most systems are consistent with angular momentum alignment but about one-third of isolated young systems exhibit primordial misalignment. This suggests that some obliquities identified in planetary systems at older ages—including the Sun’s modest misalignment with planets in the Solar System—could originate from initial conditions of their formation.

DOI: 10.1038/s41586-025-09324-0

Source: https://www.nature.com/articles/s41586-025-09324-0