The Comparative Exploration of the Ice Giant Planets with Twin Spacecraft: Unveiling the History of our Solar System
Diego Turrini, Romolo Politi, Roberto Peron, Davide Grassi, Christina Plainaki, Mauro Barbieri, David M. Lucchesi, Gianfranco Magni, Francesca Altieri, Valeria … 展开作者
Diego Turrini, Romolo Politi, Roberto Peron, Davide Grassi, Christina Plainaki, Mauro Barbieri, David M. Lucchesi, Gianfranco Magni, Francesca Altieri, Valeria Cottini, Nicolas Gorius, Patrick Gaulme, François-Xavier Schmider, Alberto Adriani, Giuseppe Piccioni
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29 pages, 4 figures; accepted for publication on the special issue "The outer Solar System X" of the journal Planetary and Space Science. This article presents an updated and expanded discussion of the white paper "The ODINUS Mission Concept" (arXiv:1402.2472) submitted in response to the ESA call for ideas for the scientific themes of the future L2 and L3 space missions
In the course of the selection of the scientific themes for the second and third L-class missions of the Cosmic Vision 2015-2025 program of the European Space Agency, the exploration of the ice giant planets Uranus and Neptune was defined "a timely milestone, fully appropriate for an L class mission". Among the proposed scientific themes, we presented the scientific case of exploring both planets and their satellites in the framework of a single L-class mission and proposed a mission scenario that could allow to achieve this result. In this work we present an updated and more complete discussion of the scientific rationale and of the mission concept for a comparative exploration of the ice giant planets Uranus and Neptune and of their satellite systems with twin spacecraft. The first goal of comparatively studying these two similar yet extremely different systems is to shed new light on the ancient past of the Solar System and on the processes that shaped its formation and evolution. This, in turn, would reveal whether the Solar System and the very diverse extrasolar systems discovered so far all share a common origin or if different environments and mechanisms were responsible for their formation. A space mission to the ice giants would also open up the possibility to use Uranus and Neptune as templates in the study of one of the most abundant type of extrasolar planets in the galaxy. Finally, such a mission would allow a detailed study of the interplanetary and gravitational environments at a range of distances from the Sun poorly covered by direct exploration, improving the constraints on the fundamental theories of gravitation and on the behaviour of the solar wind and the interplanetary magnetic field.
Ultima Thule: a Prediction for the Origin, Bulk Chemical Composition, and Physical Structure, submitted prior to the New Horizons Spacecraft 100 Pixel LORRI Data Return
Ring Seismology of the Ice Giants Uranus and Neptune
我们评估的前景，使用环地震探测冰巨人天王星和海王星的内部。我们这样做，通过计算正常模式光谱不同的内部模型的天王星和海王星使用恒星振荡代码GYRE。这些光谱提供了预测，在这些行星的环系统中，可能会检测到内部振荡的影响。我们发现，f-模式共振与方位阶$m=2$或$7 \leq m \leq 19$之间的内环（6，5，4，$α$，和$β$）的天王星，而f-模式共振与$2 \leq m \leq 12$落在纤细的$ζ$环区域。此外，与$m=2$或$6 \leq m \leq 13$的f模式共振可能会给海王星的脆弱加勒环带来方位角结构。我们还发现，g模式共振可能落在这些行星的中间到外环。虽然最有可能需要一个轨道器来确认环中的任何波与行星简正模之间的关联，但简正模光谱的多样性意味着，在天王星或海王星环中识别出一个或两个模式将消除各种内部模型，从而有助于解释旅行者观测和未来的航天器测量。
Comet 21P/Giacobini-Zinner: Water Production Activity over 20 Years with SOHO/SWAN
1985年，21 P/Giacobini-Zinner彗星是第一颗被国际彗星探测器（ICE）探测到的彗星，比1986年的哈雷彗星探测器早了几个月。ICE最初是ISEE-3卫星，设计用于地球附近的磁层测量，并通过月球重力辅助转向穿过彗星的等离子体尾部。这颗彗星在1998年，2005年，2012年和2018年的最后四次出现期间被太阳和日光层观测卫星上的全天空氢莱曼α太阳风各向异性（SWAN）相机观测到。本文比较了Combi等人（2011年）发表的1998年和2005年氢图像计算的产水率，以及2012年和2018年的新观测结果。与一些随着时间推移而褪色的彗星不同，除了2012年的结果中看到的两次爆发外，彗星21 P的活动水平并没有随着时间的推移而发生一致的变化。对所有四次出现的近日点前的产水率与日心距离进行幂律拟合，得到的结果为3.75 x 10^28 x r^-0.28+/-0.4，而对近日点后的产水率，扣除2012年以爆发为主的数据，得到的结果为4.15 x 10^28 x r^-10.2+/-0.9。产生率以s^-1为单位，日心距离以AU为单位。
Unveiling Complex Chemistry in Planet-forming Disks with the SKAO
University of Leeds（利兹大学）；Univ Toulouse, CNES, CNRS, IRAP（图卢兹大学，法国国家空间研究中心，法国国家科学研究中心，天体物理研究所）；Academia Sinica Institute of Astronomy and Astrophysics（中央研究院天文及天文物理研究所）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；Tata Institute of Fundamental Research（塔塔基础研究所）；Institute for Research in Fundamental Sciences（伊朗基础科学研究院）；United Kingdom Astronomy Technology Centre（英国天文学技术研究中心）；National Institute of Science Education and Research（国家科学教育与研究学院）；Homi Bhabha National Institute（霍米·巴哈国立学院）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Monash University（蒙纳士大学）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；University of Leicester（莱斯特大学）
