近日，厦门大学任彬团队研究了北落师门星系的第二次星子碰撞。相关论文于2025年12月18日发表在《科学》杂志上。

附近的恒星北落师门（Fomalhaut）被一个致密源——北落师门b（Fomalhaut b）环绕。此前，该天体被解释为一颗被尘埃包裹的系外行星，或者是由两颗星子碰撞产生的尘埃云。此类碰撞很少被观测到，但其产生的碎片可以通过直接成像显现。

研究组报告了哈勃空间望远镜的观测结果，显示在2023年，北落师门周围出现了第二个点状源，其外观与二十年前北落师门b的出现相似。研究组解释这个新增的源是由最近两颗星子碰撞产生的尘埃云。这两个由撞击产生的尘埃云在二十年间的的位置和运动，为研究碎片带中的碰撞动力学提供了约束条件。

附：英文原文

Title: A second planetesimal collision in the Fomalhaut system

Author: Paul Kalas, Jason J. Wang, Maxwell A. Millar-Blanchaer, Bin B. Ren, Mark C. Wyatt, Grant M. Kennedy, Maximilian Sommer, Thomas M. Esposito, Robert J. De Rosa, Michael Fitzgerald

Issue&Volume: 2025-12-18

Abstract: The nearby star Fomalhaut is orbited by a compact source, Fomalhaut b, which has previously been interpreted as either a dust-enshrouded exoplanet or a dust cloud generated by the collision of two planetesimals. Such collisions are rarely observed but their debris can appear in direct imaging. We report Hubble Space Telescope observations that show the appearance in 2023 of a second point source around Fomalhaut, resembling the appearance of Fomalhaut b twenty years earlier. We interpret this additional source as a dust cloud produced by a recent impact between two planetesimals. The positions and motion of two impact-generated dust clouds over twenty years provide constraints on the collisional dynamics in the debris belt.

DOI: adu6266

Source: https://www.science.org/doi/10.1126/science.adu6266