Active Asteroid 311P/PanSTARRS: Rotational Instability as the Origin of its Multitails?
Active Asteroid 311P/PanSTARRS: Rotational Instability as the Origin of its Multitails?
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DOI：
10.3847/1538-3881/acf31c
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发表时间：
2023-09
期刊：
影响因子：
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通讯作者：
Bin Liu;Xiaodong Liu;Xiaoyu Jia;Fei Li;Yuhui Zhao;LiangLiang Yu
中科院分区：
文献类型：
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作者：
Bin Liu;Xiaodong Liu;Xiaoyu Jia;Fei Li;Yuhui Zhao;LiangLiang Yu
活跃的小行星311P/PanSTARRS是计划中的中国小行星探测任务天文二号的两个目标之一。在2013年期间，311P经历了几次质量损失事件，并出现了多个彗星状的尾巴。在这里，我们分析了尾巴的形态和表面亮度，以研究原子核周围的尘埃环境和活动机制。我们利用图像处理技术来增强尾部的特征，以获得关于尾部形态的信息，并将处理后的图像与同步偏振图进行拟合。拟合结果给出了喷发持续时间上限(2-8天)和尾部粉尘大小范围(0.006-38.9 mm)的估计值。对每个尘埃尾巴进行的表面光度测量结果表明，每个尘埃尾巴的亮度分布指数大约在−1.81到0之间，311P尾巴的尘埃粒度分布指数在−2.29到−1.45之间。每条尾巴中的粒子数量在0.5~8×10~6公斤之间，导致总的尘埃损失量为3.0×10~7公斤，质量损失率为1.59公斤S−1。排除了行星升华、连续撞击或潮汐作用力对311P活动的解释，旋转不稳定性仍然是一个可能的激活原因，没有强有力的证据支持。
The active asteroid 311P/PanSTARRS is one of the two targets of the planned Chinese asteroid exploration mission Tianwen-2. During 2013, 311P experienced several mass-loss events and exhibited multiple comet-like tails. Here we analyze the morphology and surface brightness of the tails to investigate the dust environment around the nucleus and the mechanism of activities. We enhance the features of the tails using image processing techniques to obtain information about the morphologies of the tails, and fit the processed images with syndyne–synchrone diagrams. The fitting results give estimations of the upper limits of the durations (2–8 days) of eruptions and the dust size ranges (0.006 –38.9 mm) in the tails. The results of surface photometry performed for each dust tail show that the brightness distribution index of each tail ranged from approximately −1.81 to 0 and the dust size distribution indices of 311P's tails ranged from −2.29 to −1.45. The quantity of particles in each tail ranged from 0.5 to 8 × 106 kg, which leads to a total dust-loss quantity of 3.0 × 107 kg and a mass-loss rate of 1.59 kg s−1. Sublimation, continuous impacts, or tidal forces of planets are excluded as explanations for 311P’s activities, and rotational instability remains a possible activation cause without strong evidence against it.