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arXiv 2312.11642astro-ph.EP
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利用Gaia DR2天体测量数据测定小行星质量的挑战

The Challenge of Measuring Asteroid Masses with Gaia DR2 astrometry

Zachary Murray

AI总结:

本研究分析利用Gaia DR2天体测量数据测定小行星质量的挑战,识别有价值的小行星交会事件,量化质量测定误差,指出多数情况下约束宽松,最小小行星质量测定需额外观测数据,并给出优先研究的交会事件列表。

摘要:

Gaia第二次数据发布(Gaia DR2)包含了数千颗太阳系天体的高精度天体测量数据。这些测量数据使得通过建模Gaia观测到的大质量天体之间的散射事件来测定小行星质量成为可能。在本文中,我们识别了第二次数据发布期间发生的小型小行星之间具有研究价值的交会事件,并量化了质量测定过程中涉及的各类误差。我们认为,在最佳情况下,Gaia天体测量数据可对小行星位置提供精度高达1千米的约束。此外,我们发现即使进行了广义相对论修正,太阳系轨道积分在700天后仍会累积1千米的误差。尽管这一误差对DR2天体测量建模而言不成问题,但未来的Gaia数据发布可能需要考虑额外效应的模型,例如太阳和行星的引力谐量。另外,由于天体测量不确定性未达最优、观测几何结构以及Gaia的观测模式,大多数情况下的约束要宽松得多,部分情况下约束强度会弱几个数量级。这表明,要对最小型的小行星进行准确的质量测定,需要额外的观测数据,要么来自未来的Gaia数据发布,要么来自其他数据源。我们提供了一份最具进一步研究价值的交会事件列表。

英文摘要:

The Gaia second data release contains high-accuracy astrometric measurements of thousands of solar system bodies. These measurements raise the possibility of determining asteroid masses by modeling scattering events between massive objects observed by Gaia. In this paper, we identify promising encounters between small asteroids that occur during the second data release and quantify the various errors involved in mass determination. We argue that in the best case, Gaia astrometry can provide constraints as tight as 1 km on the positions of asteroids. Further, we find that even with general relativistic corrections, integrations of the solar system accumulate 1 km errors after 700 days. While not a problem for modeling DR2 astrometry, future Gaia data releases may require models accounting for additional effects such as gravitational harmonics of the sun and planets. Additionally, due to sub-optimal astrometric uncertainty, the geometry of the observations, and the Gaia observing pattern result in much looser constraints in most cases, with constraints being several orders of magnitude weaker in some cases. This suggests that accurate mass determination for the smallest asteroids will require additional observations, either from future Gaia data releases or from other sources. We provide a list of encounters that are most promising for further investigation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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