ORBITS AND MASSES OF THE SATELLITES OF THE DWARF PLANET HAUMEA (2003 EL61)
ORBITS AND MASSES OF THE SATELLITES OF THE DWARF PLANET HAUMEA (2003 EL61)
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DOI：
10.1088/0004-6256/137/6/4766
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
D. Ragozzine;Michael E. Brown
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文献类型：
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作者：
D. Ragozzine;Michael E. Brown
利用哈勃太空望远镜和W.M.Keck望远镜的精密相对天体测量，我们确定了矮行星(136108)Haumea(前身为2003EL61)的两颗动态相互作用卫星的轨道和质量。较明亮的外层卫星Hi‘iaka的轨道参数与之前推导出的轨道很好地匹配。在长于几周的时间尺度上，任何开普勒式的轨道都不足以描述内部较暗的卫星Namaka的运动。利用完全相互作用的三点质量模型，我们恢复了两个轨道的轨道参数以及Haumea和Hi‘iaka的质量；Namaka的质量被边缘检测到。这些数据不足以唯一地确定非球形主星的引力四极矩(由J2描述)。卫星的近乎共面的性质，以及推断的类似于水冰的密度，强化了豪美亚在数十亿年前经历过一次巨大碰撞的假设。激发的偏心和相互倾斜指向了一段有趣的潮汐历史，即通过卫星平均运动共振进行重要的半长轴演化。轨道解表明，Namaka和Haumea目前正在经历相互的事件，共同事件季节将持续未来几年。
Using precise relative astrometry from the Hubble Space Telescope and the W. M. Keck Telescope, we have determined the orbits and masses of the two dynamically interacting satellites of the dwarf planet (136108) Haumea, formerly 2003 EL61. The orbital parameters of Hi'iaka, the outer, brighter satellite, match well the previously derived orbit. On timescales longer than a few weeks, no Keplerian orbit is sufficient to describe the motion of the inner, fainter satellite Namaka. Using a fully interacting three-point-mass model, we have recovered the orbital parameters of both orbits and the mass of Haumea and Hi'iaka; Namaka's mass is marginally detected. The data are not sufficient to uniquely determine the gravitational quadrupole of the nonspherical primary (described by J2). The nearly coplanar nature of the satellites, as well as an inferred density similar to water ice, strengthen the hypothesis that Haumea experienced a giant collision billions of years ago. The excited eccentricities and mutual inclination point to an intriguing tidal history of significant semimajor axis evolution through satellite mean-motion resonances. The orbital solution indicates that Namaka and Haumea are currently undergoing mutual events and that the mutual event season will last for next several years.