Rosetta mission results pre-perihelion Special feature Comparison of 3 D kinetic and hydrodynamic models to ROSINA-COPS measurements of the neutral coma of 67 P / Churyumov-Gerasimenko
Rosetta mission results pre-perihelion Special feature Comparison of 3 D kinetic and hydrodynamic models to ROSINA-COPS measurements of the neutral coma of 67 P / Churyumov-Gerasimenko
复制标题
DOI：
--
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
A. Bieler;K. Altwegg;H. Balsiger;J. Berthelier;U. Calmonte;M. Combi;J. Keyser;B. Fiethe;N. Fougere;S. Fuselier;S. Gasc;T. Gombosi;K. Hansen;M. Hässig;Zhenguang Huang;A. Jäckel;X. Jia;L. L. Roy-L.;U. Mall;H. Rème;M. Rubin;V. Tenishev;G. Tóth;C. Tzou;P. Wurz
中科院分区：
文献类型：
--
作者：
A. Bieler;K. Altwegg;H. Balsiger;J. Berthelier;U. Calmonte;M. Combi;J. Keyser;B. Fiethe;N. Fougere;S. Fuselier;S. Gasc;T. Gombosi;K. Hansen;M. Hässig;Zhenguang Huang;A. Jäckel;X. Jia;L. L. Roy-L.;U. Mall;H. Rème;M. Rubin;V. Tenishev;G. Tóth;C. Tzou;P. Wurz
67 P/Churyumov-Gerasimenko（67 P）是一颗彗星家族，也是欧洲航天局罗塞塔使命的研究对象。这份报告提出了67 P的中性气体彗发的第一个完整的三维模拟结果。在这项研究中，我们包括直接模拟蒙特卡罗方法，流体动力学代码，和一个纯粹的几何计算，计算总照明的表面面积的核的结果。所有模型包括67 P的三角形3D形状模型以及逼真的照明和阴影条件。基本概念是假设这些照明条件的核心是主要的驱动程序的气体活动的彗星。因此，67 P的总生产率随太阳日射量而变化。当夜间侧的气体通量在最大通量的7%至10%的范围内时，模型和数据之间的最佳一致性得以实现，占最易挥发组分的贡献。为了验证我们的数值模拟的输出，我们比较所有三个模型的结果，从ROSINA COPS仪器在现场气体数密度测量。我们能够重现这些本地中性数密度测量的整体特征ROSINA COPS的时间段之间的2014年8月上旬和2015年1月1日与所有三个模型。测量中的一些细节没有重现，需要进一步调查和改进模型。然而，总的假设，照明条件的核至少是一个重要的驱动程序的气体活动的验证模型。根据我们的模拟结果，我们发现2014年8月至11月期间67 P的总产生速率保持不变，约为1 × 1026个分子s-1。
67P/Churyumov-Gerasimenko (67P) is a Jupiter-family comet and the object of investigation of the European Space Agency mission Rosetta. This report presents the first full 3D simulation results of 67P’s neutral gas coma. In this study we include results from a direct simulation Monte Carlo method, a hydrodynamic code, and a purely geometric calculation which computes the total illuminated surface area on the nucleus. All models include the triangulated 3D shape model of 67P as well as realistic illumination and shadowing conditions. The basic concept is the assumption that these illumination conditions on the nucleus are the main driver for the gas activity of the comet. As a consequence, the total production rate of 67P varies as a function of solar insolation. The best agreement between the model and the data is achieved when gas fluxes on the night side are in the range of 7% to 10% of the maximum flux, accounting for contributions from the most volatile components. To validate the output of our numerical simulations we compare the results of all three models to in situ gas number density measurements from the ROSINA COPS instrument. We are able to reproduce the overall features of these local neutral number density measurements of ROSINA COPS for the time period between early August 2014 and January 1 2015 with all three models. Some details in the measurements are not reproduced and warrant further investigation and refinement of the models. However, the overall assumption that illumination conditions on the nucleus are at least an important driver of the gas activity is validated by the models. According to our simulation results we find the total production rate of 67P to be constant between August and November 2014 with a value of about 1 × 1026 molecules s−1.