论文标题
昏迷各向异性和星际彗星2i/borisov的旋转杆
Coma Anisotropy and the Rotation Pole of Interstellar Comet 2I/Borisov
论文作者
论文摘要
围绕周围的星际彗星2i/borisov的哈勃空间望远镜观察显示，<〜9 m/s速度的大（> 〜100 um）颗粒的射出，估计质量损失率为〜35 kg/s。 Borisov彗星的总质量损失对应于仅〜0.4 m厚的核上表面壳的丧失。该壳足够薄，可以通过宇宙射线在星际介质中过去的化学处理，这意味着不一定会认为弹出的材料是原始的。我们的高分辨率图像揭示了尘埃昏迷的持续不对称性，最好是通过旋转核上的热滞后滞后，导致峰质量损失发生在彗星核下午。在这种解释中，核以倾斜为30度旋转（极方向RA = 205度，dec. = 52 ver）。从发现时-35摄氏度（南冬至）到1月2020年的0度（Equinox）不等，这表明季节性影响的重要性。随后的活动可能是由于北半球首次照亮的新地区而引起的。
Hubble Space Telescope observations of interstellar comet 2I/Borisov near perihelion show the ejection of large (>~100 um) particles at <~9 m/s speeds, with estimated mass-loss rates of ~35 kg/s. The total mass loss from comet Borisov corresponds to loss of a surface shell on the nucleus only ~0.4 m thick. This shell is thin enough to be susceptible to past chemical processing in the interstellar medium by cosmic rays, meaning that the ejected materials cannot necessarily be considered as pristine. Our high-resolution images reveal persistent asymmetry in the dust coma, best explained by a thermal lag on the rotating nucleus causing peak mass loss to occur in the comet nucleus afternoon. In this interpretation, the nucleus rotates with an obliquity of 30 deg (pole direction RA = 205 deg and Dec. = 52 deg). The subsolar latitude varied from -35 deg (southern solstice) at the time of discovery to 0 deg (equinox) in 2020 January, suggesting the importance of seasonal effects. Subsequent activity likely results from regions freshly activated as the northern hemisphere is illuminated for the first time.
