Post-perihelion Coma Composition of the Interstellar Comet 3I/ATLAS from Optical Spectroscopy
CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台光学天文重点实验室）；Yunnan Observatories, Chinese Academy of Sciences (CAS)（中国科学院云南天文台）；School of Astronomy and Space Sciences, University of Chinese Academy of Sciences（中国科学院大学天文学与空间科学学院）；Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales（迭戈帕托莱斯大学工程与科学学院天体物理研究所）；Planetary Science Institute（行星科学研究所）
Ruining Zhao, Xiliang Zhang, Bin Yang, Xiangyu Fan, Shu Wang, Yang Huang, Jifeng Liu
备注：
20 pages, 4 figures, 6 tables, accepted for publication in ApJL
We present multi-epoch optical spectroscopy of the interstellar comet 3I/ATLAS obtained between December 2025 and January 2026 (heliocentric distances 1.8-3.3 au), yielding post-perihelion production rates and mixing ratios for CN, C$_3$, C$_2$, CH, and gaseous metals (Fe I and Ni I). Our results show that the coma is less depleted in C$_2$ after perihelion than before, indicative of subsurface activation or compositional heterogeneity. The outgassing profiles reveal a pronounced perihelion asymmetry: CN and metal production rates decline more gradually outbound than inbound, consistent with the reported behavior of H$_2$O and implying a change in the comet's activity pattern across perihelion. Despite being metal-rich relative to its H$_2$O content, 3I follows the metal-CO correlation observed in comets of diverse origins, suggesting that gaseous metal release is more closely linked to a CO-bearing volatile reservoir than to H$_2$O, potentially in the form of metal carbonyls. In addition, the [O I] $\lambda6300$ emission shows a significant residual after subtracting the expected contributions from H$_2$O, CO$_2$, and CO, which may reflect systematic uncertainties in the photodissociation yields of those molecules or a contribution from additional oxygen-bearing parents.
Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS
Universidad Diego Portales（迭戈帕托莱斯大学）；Planetary Science Institute（行星科学研究所）；Georgia Institute of Technology（佐治亚理工学院）；University of Illinois Urbana-（伊利诺伊大学厄巴纳-）
Water Production of Interstellar Comet 3I/ATLAS from SOHO/SWAN Observations after Perihelion
University of Michigan（密歇根大学）；Finnish Meteorological Institute（芬兰气象局）；LATMOS/IPSL UVSQ Université Paris-Saclay, Sorbonne Université, CNRS（巴黎萨克雷大学、索邦大学、法国国家科学研究中心LATMOS/IPSL联合实验室）；ACRI-st；LIRA, Observatoire de Paris（巴黎天文台LIRA）
利用SOHO/SWAN观测，研究星际彗星3I/ATLAS水生产率，发现其在近日点后9天的水生产率为3.17 x 10^29 s^-1，随后逐渐下降。
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species
Johns Hopkins University Applied Physics Laboratory（约翰斯·霍普金斯大学应用物理实验室）；Korea Astronomy and Space Science Institute（韩国天体宇宙科学研究所）；Arizona State University（亚利桑那州立大学）；California Institute of Technology（加州理工学院）；Jet Propulsion Lab（喷气推进实验室）；University of California Irvine（加州大学尔湾分校）；Infrared Processing and Analysis Center, Caltech（加州理工学院红外处理与分析中心）；Center for Astrophysics, Harvard & Smithsonian（哈佛-史密森尼天体物理中心）
Dust colour, phase behaviour, and Monte Carlo modelling of interstellar comet 3I/ATLAS from 4 au pre- to 4 au post-perihelion
Instituto de Astrofísica de Andalucía, CSIC（安达卢西亚天体物理研究所）；Light Bridges, Observatorio Astronómico del Teide（光桥望远镜台）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Departamento de Astrofísica, Universidad de La Laguna（拉帕尔马大学天体物理学系）
Perihelion observations of interstellar comet 3I/ATLAS with the IRAM 30-m telescope
LIRA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, Université de Paris（巴黎天文台）；IRAM（红外毫米波天文台）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；Department of Physics, Catholic University of America（美利坚天主教大学物理系）；Department of Physics, American University（美利坚大学物理系）
Origin and evolution of NiI and FeI in the coma of the interstellar comet 3I/ATLAS throughout its trajectory
Université de Liège（列日大学）；University of Edinburgh（爱丁堡大学）；Université Catholique de Louvain（天主教鲁汶大学）；University of Canterbury（坎特伯雷大学）；Auburn University（奥本大学）；University of Helsinki（赫尔辛基大学）；University of Padova（帕多瓦大学）
研究揭示了镍和铁在星际彗星3I/ATLAS彗核 coma 中的起源与演化，发现其金属产量显著高于太阳系彗星，并提出羰基假说解释其形成机制。
Multi-Wavelength Post-Perihelion Polarimetry of Interstellar Comet 3I/ATLAS
University of Helsinki（赫尔辛基大学）；Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences（保加利亚科学院天文研究所与国家天文台）；Armagh Observatory & Planetarium（阿马天文台与天文馆）；University of Maryland（马里兰大学）；TU Braunschweig（布伦瑞克工业大学）；INAF – Osservatorio Astrofisico di Torino（意大利国家天体物理研究所都灵天文台）；Finnish Centre for Astronomy with ESO, University of Turku（图卢大学ESO芬兰天文学中心）；Luleå University of Technology（吕勒奥理工大学）
Pre-perihelion evolution of the NiI/FeI abundance ratio in the coma of the interstellar comet 3I/ATLAS. From extreme to normal
Université de Liège（列日大学）；University of Edinburgh（爱丁堡大学）；Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学）；University of Canterbury（坎特伯雷大学）；University of Helsinki（赫尔辛基大学）
Post-perihelion Photometric and Spectroscopic Monitoring of the Interstellar Comet 3I/ATLAS
Physical Research Laboratory（物理研究实验室）；Indian Institute of Technology Gandhinagar（甘地纳加尔印度理工学院）；Space sciences, Technologies & Astrophysics Research (STAR) Institute, University of Liège（列日大学空间科学、技术与天体物理研究（STAR）研究所）；Cepheid Observatory（造父变星天文台）；Department of Physics and Astronomy, University of Nebraska-Lincoln（内布拉斯加大学林肯分校物理与天文学系）
Very Large Telescope observations of interstellar comet 3I/ATLAS III: High-resolution monitoring of CN and forbidden oxygen emission across the perihelion passage with ESPRESSO
Pre-perihelion observations of comet P/2023 JN16 (Lemmon) at the 2024 apparition
Main Astronomical Observatory of NAS of Ukraine（乌克兰国家科学院主天文台）；Astronomical Observatory of Taras Shevchenko National University of Kyiv（基辅塔拉斯舍甫琴科国立大学天文台）；Research School of Astronomy and Astrophysics, Australian National University（澳大利亚国立大学天体物理学与天文学研究学院）
A translation of L. Euler's "On the motion of comets in parabolic orbits, having the Sun in the focus"
这是从拉丁文E840“De motu cometarum in orbitis parabolarian，solem in foco habentibus”的翻译，其中欧拉解决了六个与日心抛物轨道彗星有关的问题。问题1：从轨道的横距和地球到太阳的中等距离找到一颗日心彗星的真正异常。问题2：从三个给定的位置找到日心彗星的轨道。问题3：知道彗星的轨道，以及它停留在近日点的时刻，就可以定义它在任何时候的经度和纬度。问题四：从日心彗星的两个位置，找出彗星轨道相对于黄道的倾角，以及交点的位置。问题五：从彗星到达近日点之前或之后的时间，以及从太阳上看到的彗星到近日点的距离，找到在它出现在近日点之前或之后的另一个时间的相同距离。问题6：从三个给定的日心坐标和纬度找到彗星的轨道。从这些问题，几个推论和scholia派生。
Dynamically New Comet C/2025 D1 (Groeller) with Record Perihelion Distance
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；The University of Western Ontario（韦仕敦大学）；ESA NEO Coordination Centre, Planetary Defence Office（欧洲空间局近地天体协调中心行星防御办公室）
