海王星的第七个月亮
M R Showalter1, I de Pater2, J J Lissauer3
1SETI Institute, Mountain View, CA, USA. mshowalter@seti.org.
Nature
|February 22, 2019
概括
旅行者2号发现了海王星的七个内部卫星, 哈勃太空望远镜的观测表明海马是卫星普罗蒂乌斯的碎片,可能是由彗星撞击形成的.
科学领域:
- 星球科学
- 天文学
- 海王星系统动力学
背景情况:
- 旅行者2号在1989年拍摄了海王星内部的六颗卫星,
- 这些卫星和海王星的环,很可能比海王星年轻,并且因彗星撞击而碎片化.
- 内部的卫星被认为是在Triton被捕获后形成的.
研究的目的:
- 报告哈勃太空望远镜对海王星第七颗内月的观测.
- 为所有内部卫星提供最新的天文测量,轨道测定和尺寸估计.
- 调查海马的起源及其与普罗蒂乌斯的关系.
主要方法:
- 利用哈勃太空望远镜的观测图像拍摄海王星的内部卫星.
- 采用图像分析技术,包括扭曲连续图像以弥补轨道运动.
- 对纳亚德,希波坎普和其他内部卫星进行了天文测量和轨道测定.
主要成果:
- 证实了希波坎普的存在, 这是一个半径约17公里的小卫星.
- 观测到海王星最内层的卫星纳亚德, 自1989年以来没有见过它.
- 确定Hippocamp的轨道接近Proteus,其半主要轴的差异为10%,这表明Hippocamp是Proteus的片段.
结论:
- 希波坎普可能是普罗蒂乌斯的古老碎片, 支持内海王星系统进化的撞击假说.
- 使用的分析技术可能适用于发现其他卫星和系外行星.
- 海王星的内部系统随着时间的推移而被大量撞击所塑造.
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