Evolution of the dust coma in comet 67P/Churyumov-Gerasimenko before the 2009 perihelion
Evolution of the dust coma in comet 67P/Churyumov-Gerasimenko before the 2009 perihelion
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2009 年近日点之前 67P/Churyumov-Gerasimenko 彗星中尘埃彗发的演化
DOI：
10.1051/0004-6361/201116577
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发表时间：
2011
影响因子：
6.5
通讯作者：
J. Stuwe
中科院分区：
文献类型：
--
作者：
G. Tozzi;P. Patriarchi;H. Boehnhardt;J. Vincent;J. Licandro;L. Kolokolova;R. Schulz;J. Stuwe
67P/Churyumov-Gerasimenko彗星是ESA罗塞塔任务的主要目标，将于2014年5月与之相遇。由于在“菲莱”号着陆器释放前后，宇宙飞船将在彗星核轨道上运行，因此有必要了解彗发的情况。研究尘埃环境，包括尘埃产生率及其沿近日点轨道的变化。从2008年6月初到2009年1月中旬，这颗彗星在接近太阳的四个时期被观测到，在很大范围内的日心距离将被2014年的任务覆盖。彗发尘埃密度向彗核方向异常增强。这种增强的尺度长度随着彗星日心距离的减小而增大。这被解释为尘埃彗发异常缓慢扩张的结果。假设彗发为球对称彗发，我们推导出了平均尘埃量及其抛射速度。后者随着日心距离（\rh）的减小呈指数增长，范围从3au时的约1米/秒到1.4 AU时的约25-35米/秒。根据这些结果，我们描述了在那些中心距离的尘埃环境，飞船可能在轨道上。
Comet 67P/Churyumov-Gerasimenko is the main target of ESA's Rosetta mission and will be encountered in May 2014. As the spacecraft shall be in orbit the comet nucleus before and after release of the lander {\it Philae}, it is necessary necessary to know the conditions in the coma. Study the dust environment, including the dust production rate and its variations along its preperihelion orbit. The comet was observed during its approach to the Sun on four epochs between early-June 2008 and mid-January 2009, over a large range of heliocentric distances that will be covered by the mission in 2014. An anomalous enhancement of the coma dust density was measured towards the comet nucleus. The scalelength of this enhancement increased with decreasing heliocentric distance of the comet. This is interpreted as a result of an unusually slow expansion of the dust coma. Assuming a spherical symmetric coma, the average amount of dust as well as its ejection velocity have been derived. The latter increases exponentially with decreasing heliocentric distance (\rh), ranging from about 1 m/s at 3 AU to about 25-35 m/s at 1.4 AU. Based on these results we describe the dust environment at those nucleocentric distances at which the spacecraft will presumably be in orbit.
Astronomy and Astrophysics, in press