Tiny Main-belt Asteroid Spectral Survey (TMASS)

微小主带小行星光谱巡天（TMASS）

• 批准号: 0708101
• 负责人: Andrew Rivkin
• 金额: $ 13.96万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0708101&HistoricalAwards=false
• 关键词: Tiny; Main; belt; Asteroid; Spectral

AST 0708101RivkinA long-standing problem in asteroid spectroscopy has been the question of whether the spectra of these bodies change with time via exposure to the solar wind and/or micrometeorite impact, a process dubbed "space weathering". Recent evidence is coalescing around the theory that space weathering does occur on asteroid surfaces, and that the 1-5 km diameter range is a critical transition size. This research program led by Dr. Andrew Rivkin will use newly-collected astronomical data to explore space weathering in a sample free of many uncertainties present in other studies.The extent and rate of space weathering on asteroids will be measured by collecting the visible and near-IR reflectance spectra of roughly 100 asteroids in the Koronis dynamical family. National facilities (the 4-m telescope at Kitt Peak and the Infrared Telescope Facility (IRTF)) as well as facilities associated with the researchers' institutions (Apache Point Observatory in New Mexico for Rivkin, the Magellan telescopes in Chile for Binzel) will be used for observations. The targets willbe objects in the 1-5 km diameter range, which have not been systematically studied in the main belt.The result of this work will be a better understanding of the surface processes on and composition of asteroids. A study of Near-Earth Object (NEO) spectra indicates that objects roughly 1 km and smaller on average show little evidence of space weathering, while those 5 km and larger have average spectra like large main-belt objects. This is consistent with the buildup of weathering products with time on asteroid surfaces. However, studies that have been done must assume the NEOs have the same composition and weathering styles and rates as each other and of main-belt asteroids. By observing small members of a dynamical family and comparing them to larger members of the same family, that issue will be removed. By establishing and measuring the degree (or absence) of space weathering in the Koronis family, the amount that spectra can change due to this process, and the road to correcting for it (as appropriate) in making compositional interpretations will be determined. The team have obtained, reduced, and published a large quantity of visible and infrared asteroid spectra, and are well-qualified to undertake this project.Establishing and characterizing the extent of space weathering on asteroids is directly applicable to understanding their composition and nature. Although not a near-term prospect, asteroid mining applications will be interested in determining the true composition of surfaces, not the weathered appearance. The same is true of NEO mitigation concerns; a metal-rich object could appear so due to space weathering or a high concentration of metal. This study will help unravel those twopossibilities, which are of obvious importance if such an object had to be deflected or destroyed. The data collected will be made publicly available as quickly as is practical. The research team have done this before for other data, as part of the NSF-funded MIT-IRTFUHNEO survey (http://smass.mit.edu/minus.html).***

AST 0708101 Rivkin小行星光谱学中一个长期存在的问题是，这些天体的光谱是否会因暴露在太阳风和/或微陨石撞击下而随时间变化，这一过程被称为“空间风化”。 最近的证据表明，小行星表面确实会发生太空风化，并且1-5公里的直径范围是关键的过渡尺寸。由Andrew Rivkin博士领导的这项研究计划将利用新收集的天文数据，在没有其他研究中存在的许多不确定性的样本中探索空间风化，将通过收集大约100颗Koronis动力家族小行星的可见光和近红外反射光谱来测量小行星空间风化的程度和速度。国家设施（基特峰的4米望远镜和红外望远镜设施（IRTF））以及与研究机构相关的设施（里夫金位于新墨西哥州的阿帕奇角天文台、宾泽尔位于智利的麦哲伦望远镜）将用于观测。目标将是直径在1-5公里范围内的物体，这些物体在主带中尚未得到系统的研究，这项工作的结果将是更好地了解小行星的表面过程和组成。对近地天体光谱的研究表明，平均约1公里和1公里以下的天体几乎没有空间风化的迹象，而5公里和5公里以上的天体具有与大型主带天体一样的平均光谱。这与小行星表面风化产物随时间的积累是一致的。然而，已经进行的研究必须假定近地天体彼此之间以及与主带小行星具有相同的组成、风化方式和速率。 通过观察一个动态家族中的小成员，并将它们与同一家族中的大成员进行比较，这个问题就可以解决了。 通过建立和测量Koronis家族中空间风化的程度（或不存在），将确定光谱由于这一过程而可能发生的变化量，以及在进行成分解释时对其进行校正（适当时）的方法。该团队已经获得、整理并公布了大量可见光和红外小行星光谱，完全有资格承担这一项目，建立和表征小行星空间风化的程度直接适用于了解其组成和性质。虽然不是近期的前景，但小行星采矿应用将对确定表面的真实成分而不是风化的外观感兴趣。对近地天体缓减的关切也是如此;富含金属的天体可能由于空间风化或金属浓度高而出现这种情况。这项研究将有助于阐明这两种可能性，如果必须使这种物体偏转或摧毁，这两种可能性显然是重要的。收集的数据将尽快公布于众。 研究小组以前曾对其他数据进行过这样的研究，作为NSF资助的MIT-IRTFUHNEO调查的一部分（http：//smass.mit.edu/minus.html）。