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arXiv 2207.06258astro-ph.SRastro-ph.EPastro-ph.GA
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接近太阳一秒差距内的恒星：在盖亚数据发布3中确定的新的和更准确的遭遇

Stars that approach within one parsec of the Sun: New and more accurate encounters identified in Gaia Data Release 3

C. A. L. Bailer-Jones

备注：
Accepted to ApJ Letters (submitted 18 June 2022). Minor typos corrected in arXiv v2. For more plots see https://www.mpia.de/homes/calj/stellar_encounters_gdr3.html
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摘要：

恒星与太阳的近距离相遇可能会通过奥尔特云中彗星的引力扰动或暴露于电离辐射而影响地球上的生命。通过整合轨道通过银河系的潜力，我确定在盖亚DR 3与完整的相空间信息的3300万颗恒星接近太阳。61颗恒星在1 pc内正式接近，尽管其中只有42颗（三分之二）具有高置信度，其余的是虚假测量或（在）双星系统中。大多数恒星将在过去或未来的600万年内相遇;由于盖亚径向速度（RV）的大小限制，早期/晚期的相遇不太常见。几颗近距离相遇的恒星首次被确认，并且由于盖亚DR 3的精度比早期版本有了显着提高，以前已知的近距离相遇的相遇时间，距离和速度被更精确地确定。K7矮星G1 710仍然是已知的最近相遇，估计（中位数）相遇距离为0.0636 pc（90%置信区间0.0595-0.0678 pc），发生在130万年前。新的第二次最近的遭遇发生在280万年前：这是G3矮星HD 7977，现在距离76 pc，接近太阳不到0.05 pc的概率为三分之一。白矮星UPM J 0812 -352的近距离接触可能是虚假的，因为盖亚DR 3中的RV不正确。

英文摘要：

Close encounters of stars to the Sun could affect life on Earth through gravitational perturbations of comets in the Oort cloud or exposure to ionizing radiation. By integrating orbits through the Galactic potential, I identify which of 33 million stars in Gaia DR3 with complete phase space information come close to the Sun. 61 stars formally approach within 1 pc, although there is high confidence in only 42 (two thirds) of these, the rest being spurious measurements or (in) binary systems. Most of the stars will encounter within the past or future 6 Myr; earlier/later encounters are less common due to the magnitude limit of the Gaia radial velocities (RVs). Several close encountering stars are identified for the first time, and the encounter times, distances, and velocities of previously known close encounters are determined more precisely on account of the significantly improved precision of Gaia DR3 over earlier releases. The K7 dwarf Gl 710 remains the closest known encounter, with an estimated (median) encounter distance of 0.0636 pc (90% confidence interval 0.0595-0.0678 pc) to take place in 1.3 Myr. The new second closest encounter took place 2.8 Myr ago: this was the G3 dwarf HD 7977, now 76 pc away, which approached within less than 0.05 pc of the Sun with a probability of one third. The apparent close encounter of the white dwarf UPM J0812-352 is probably spurious due to an incorrect RV in Gaia DR3.

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