Location, orbit and energy of a meteoroid impacting the moon during the Lunar Eclipse of January 21, 2019
Jorge I. Zuluaga, Matipon Tangmatitham, Pablo A. Cuartas-Restrepo, Jonathan Ospina, Fritz Pichardo, Sergio A. Lopez, Karls Pena, J. Mauricio Gaviria-Posada
During lunar eclipse of January 21, 2019 a meteoroid impacted the Moon producing a visible light flash. The impact was witnessed by casual observers offering an opportunity to study the phenomenon from multiple geographical locations. We use images and videos collected by observers in 7 countries to estimate the location, impact parameters (speed and incoming direction) and energy of the meteoroid. Using parallax, we achieve determining the impact location at lat. $-29.43^{+0.30}_{-0.21}$, lon. $-67.89^{+0.07}_{-0.09}$ and geocentric distance as 356553 km. After devising and applying a photo-metric procedure for measuring flash standard magnitudes in multiple RGB images having different exposure times, we found that the flash, had an average G-magnitude $\langle G\rangle = 6.7\pm0.3$. We use gravitational ray tracing (GRT) to estimate the orbital properties and likely radiant of the impactor. We find that the meteoroid impacted the moon with a speed of $14^{+7}_{-6}$ km/s (70% C.L.) and at a shallow angle, $θ< 38.2$ degrees. Assuming a normal error for our estimated flash brightness, educated priors for the luminous efficiency and object density, and using the GRT-computed probability distributions of impact speed and incoming directions, we calculate posterior probability distributions for the kinetic energy (median $K_{\rm med}$ = 0.8 kton), body mass ($M_{\rm med}$ = 27 kg) and diameter ($d_{\rm med}$ = 29 cm), and crater size ($D_{\rm med}$ = 9 m). If our assumptions are correct, the crater left by the impact could be detectable by prospecting lunar probes. These results arose from a timely collaboration between professional and amateur astronomers which highlight the potential importance of citizen science in astronomy.
A Near-Earth Object Model Calibrated to Earth Impactors
Curtin University（科廷大学）；International Centre for Radio Astronomy Research, Curtin University（科廷大学国际射电天文学研究中心）；Space Science and Technology Centre, Curtin University（科廷大学空间科学与技术中心）；Southwest Research Institute（西南研究所）；NASA Astromaterials Research and Exploration Science Division, Johnson Space Center（美国国家航空航天局约翰逊航天中心天体材料研究与探索科学部）；SETI Institute（搜寻地外文明研究所）；Astronomical Society of Victoria（维多利亚天文学会）；University of Sharjah（沙迦大学）；Sharjah Academy for Astronomy, Space Sciences and Technology（沙迦天文学、空间科学与技术学院）；Faculty of Sciences Semlalia（塞姆拉利亚理学院）
Erosion of volatiles by micro-meteoroid bombardment on Ceres, and comparison to the Moon and Mercury
(1)谷神星是主带中最大的水库，黎明号宇宙飞船最近访问了它，发现了几个带有H PDMATHAMM O冰特征的区域。独立的望远镜观测显示了一个目前未知来源的水散逸层。我们探讨流星体的影响谷神星考虑到从黎明任务获得的地形，使用广泛使用的微流星体模型和射线跟踪技术。考虑直径为$0.01-2$ mm的流星体群。我们分析了谷神星在当前轨道上的短期影响以及整个岁差周期的长期影响。我们发现整个表面都受到流星体的轰击，没有留下任何区域处于流星体流入的永久阴影中。谷神星的赤道部分产生的$80\%$喷出物比极地地区多，这是因为长周期彗星的撞击速度很大。质量通量，能量通量，和喷出物生产季节性变化的$3-7$的因素，由于倾斜的偏心轨道。与水星和月球相比，谷神星经历的微流星体撞击的影响要小得多，总质量流量为$4.5\pm1.2\times10^{-17}$ kg m $^{-2}$ s $^{-1}$。平均而言，水星受到更大的$50\times$质量通量，并产生比谷神星更多的喷出物$700\times$，而月球的质量通量是$10\times$更大，喷出物的产生是$30\times$大于谷神星。由于这些原因，我们发现流星体的影响是一个不太可能的候选人生产的水散逸层或显着挖掘的表面特征。所考虑的微流星体群的表面更新率估计为谷神星上的$1.25$百万年。
Twin Impact Lunar Telescope network: Lunar Impact Flash observations of the 2025 Geminids
University of Leicester（莱斯特大学）；Université Côte d’Azur（蔚蓝海岸大学）；Observatoire de la Côte d’Azur（蔚蓝海岸天文台）；Université Paris Cité（巴黎西岱大学）；Institut de Physique du Globe de Paris（巴黎地球物理研究所）；LTE, Observatoire de Paris, Université PSL, Sorbonne Université, Université de Lille, LNE, CNRS（巴黎天文台 LTE（隶属于巴黎文理研究大学、索邦大学、里尔大学、法国国家计量院和法国国家科学研究中心））
The Dynamical Origin of Millimetre-Sized Sporadic Meteoroids
University of Western Ontario（韦仕兰大学）；NASA Goddard Spaceflight Center（美国国家航空航天局戈达德太空飞行中心）；The Catholic University of America（美利坚天主教大学）；Center for Research and Exploration in Space Science and Technology, NASA/GSFC（NASA/GSFC空间科学与技术研究探索中心）
Lunar impacts during eclipses separated by a Metonic cycle on Jan 21, 2000 and 2019: a possible origin from daytime Sagittarids/Capriconids meteor shower
Curtin University（科廷大学）；Space Science and Technology Centre, Curtin University（科廷大学空间科学与技术中心）；International Centre for Radio Astronomy Research, Curtin University（科廷大学国际射电天文研究中心）；University of Western Australia（西澳大学）；Department of Physics, University of Western Australia（西澳大学物理系）；University of the Virgin Islands（维尔京群岛大学）；International Occultation Timing Association (IOTA)（国际掩星计时协会）
