Context. Solid methane (CH$_4$) is an important molecule in interstellar and planetary environments, serving as a precursor to complex organic compounds, and it is a potential biosignature in exoplanetary studies. Despite its significance, laboratory data on the low temperature phase of methane below 10 K remain limited.
Aims. We obtained spectra of methane in binary mixtures at 10 K and compared them to the spectra obtained at 6.7 K. These temperatures correspond to phases II and II* of pure methane and are representative of dark molecular clouds and protostars in early stages. We also tested whether the data we obtained can be applied to interpret JWST data.
Methods. Laboratory reference spectra were obtained with the ISEAge setup via Fourier transform infrared spectroscopy in transmission mode. A weighted $χ^2$ minimization was used for the fitting.
Results. We present infrared spectra with corresponding band strengths of pure methane and binary mixtures with methane: CH$_4$:H$_2$O, CH$_4$:CO$_2$, CH$_4$:CH$_3$OH, and CH$_4$:NH$_3$ at 6.7 K and 10 K. They show an increase of 20% in mixtures compared to the commonly used 10 K band strength value of pure methane. We also tested whether the spectra can be used on open JWST data by probing the spatial distribution of methane in B335. We also present additional experiments concerning the phase transition of methane between phase II* and phase II.
Conclusions. Our results reveal distinct spectral features for methane in non-H$_2$O environments that enable a more accurate interpretation of JWST observations. The dataset of spectra is publicly available on Zenodo and can be used for fitting JWST data.
An Ice Age JWST inventory of dense molecular cloud ices
冰质颗粒地幔是挥发性元素的主要储存库，这些挥发性元素将黑暗星际云中的化学过程与行星的形成及其大气成分联系起来。最初的冰成分是在恒星形成之前，在分子云的寒冷、密集部分形成的。凭借JWST的灵敏度，现在可以对冰演化的这一关键阶段进行详细研究。在这里，我们展示了早期发布的科学计划“冰河时代”的第一个结果，揭示了这些致密云冰的丰富成分。弱冰，包括，$^{13}$ CO $_2$，OCN $^-$，$^{13}$ CO，OCS和COMs功能组，现在检测到沿两个星前视线。$^{12}$ CO $_2$冰剖面表明冰粒的适度增长。列密度的主要和次要的冰物种表明，冰之间的主要C，O，N，和S元素的散装预算的2%和19%。我们的研究结果表明，简单和复杂分子的形成可以在水冰丰富的环境中早期开始。
JWST detection of methane emission from a young brown dwarf
The Pennsylvania State University（宾夕法尼亚州立大学）；European Space Agency, European Space Astronomy Centre（欧洲空间局，欧洲空间天文中心）；Museum of Natural History（自然历史博物馆）；Department of Physics, The Graduate Center City University of New York（纽约城市大学研究生院物理学系）；Spectros Associates
CORINOS IV: Quantifying Baseline-Fitting Uncertainties in SO$_2$ Ice Measurements with JWST/MIRI
University of Virginia（弗吉尼亚大学）；Star and Planet Formation Laboratory, RIKEN Pioneering Research Institute（RIKEN先锋研究所星与行星形成实验室）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）；Astrochemistry Laboratory, Code 691, NASA Goddard Space Flight Center（NASA戈达德太空飞行中心天体化学实验室）；Department of Physics, Catholic University of America（美利坚天主教大学物理系）；Department of Chemistry, Virginia Military Institute（弗吉尼亚军事学院化学系）；Korea Astronomy and Space Science Institute（韩国天文学与空间科学研究院）；Department of the Geophysical Sciences, University of Chicago（芝加哥大学地球物理科学系）
JWST Edge-on Disk Ice (JEDIce): Program overview and ice survey results
University of California, Berkeley（加州大学伯克利分校）；Astrophysics & Space Institute, Schmidt Sciences（施密特科学天文与太空研究所）；Institut des Sciences Moléculaires d’Orsay, CNRS, Univ. Paris-Saclay（奥赛分子科学研究所，法国国家科学研究中心，巴黎萨克雷大学）；Physikalisch-Meteorologisches Observatorium Davos und Weltstrahlungszentrum (PMOD/WRC)（达沃斯物理气象观测站和世界辐射中心）；Institute of Astronomy, Department of Physics, National Tsing Hua University（国立清华大学物理天文学系）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）；Physique des Interactions Ioniques et Moléculaires, CNRS, Aix-Marseille Univ.（艾克斯-马赛大学离子与分子相互作用物理研究所，法国国家科学研究中心）；Center for Astrophysics, Harvard & Smithsonian（哈佛史密森尼天体物理中心）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）
A fast machine learning tool to predict the composition of astronomical ices from infrared absorption spectra
Centro de Astrobiología (CAB), CSIC-INTA（天体生物学中心）；Facultad de Ciencias Físicas, Universidad Complutense de Madrid（马德里康普顿斯大学物理科学学院）；LIRA, CY Cergy Paris Université（CY塞吉巴黎大学 LIRA 实验室）；Instituto de Estructura de la Materia (IEM), CSIC（物质结构研究所）；MasOrange；Laboratory for Astrophysics, Leiden Observatory, Leiden University（莱顿大学莱顿天文台天体物理实验室）
Mapping of interstellar ices with JWST in protostellar envelopes: Spatial variations of $^{13}$CO$_2$, $^{12}$CO$_2$, CO, OCN$^-$ and H$_2$O ice
Leiden University（莱顿大学）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理研究所）；University of Hawai’i at Manoa（夏威夷大学马诺阿分校）；University of Cambridge（剑桥大学）；Center for Astrophysics, Harvard & Smithsonian（哈佛与史密森尼天体物理中心）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；INAF-Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；The University of Toledo（托莱多大学）
The hunt for formamide in interstellar ices: A toolkit of laboratory infrared spectra in astronomically relevant ice mixtures and comparisons to ISO, Spitzer, and JWST observations
Silicate Clouds, SiO, and Molecular Trends across the L-T Sequence: A JWST/MIRI LRS Spectral Library of Brown Dwarfs
The University of Western Ontario（韦仕敦大学）；American Museum of Natural History（美国自然历史博物馆）；Centro de Astrobiología, CSIC-INTA（天体生物学中心，CSIC-INTA）；Université de Montréal（蒙特利尔大学）
JWST Observations of Young protoStars (JOYS+): Detection of icy complex organic molecules and ions. I. CH$_4$, SO$_2$, HCOO$^-$, OCN$^-$, H$_2$CO, HCOOH, CH$_3$CH$_2$OH, CH$_3$CHO, CH$_3$OCHO, CH$_3$COOH
JWST Edge-on Disk Ice (JEDIce): Vibrationally hot, rotationally cold H$_2$ in the outer disk of Oph 163131 non-thermally excited by UV and cosmic rays
University of Virginia（弗吉尼亚大学）；Virginia Institute of Theoretical Astronomy, University of Virginia（弗吉尼亚大学理论天体物理研究所）；University of California, Berkeley（加州大学伯克利分校）；Johns Hopkins University（约翰斯·霍普金斯大学）；National Tsing Hua University（国立清华大学）；Physikalisch-Meteorologisches Observatorium Davos und Weltstrahlungszentrum (PMOD/WRC)（达沃斯物理气象观测台和世界辐射中心）；Universität Bern（伯尔尼大学）；INAF-Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切尔天文台）；Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS（奥赛分子科学研究所）
EPISODE IV: Ice Inventory in the Envelope of EC 53
Korea Astronomy and Space Science Institute（韩国天文与空间科学研究所）；Seoul National University（首尔大学）；Research Institute of Basic Sciences, Seoul National University（首尔大学基础科学研究院）；RIKEN Pioneering Research Institute（理化学研究所先导研究院）；University of Tokyo（东京大学）；Peking University（北京大学）
JOYS: Linking the molecular ice and gas-phase composition towards the high-mass hot core IRAS 18089-1732
Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；Leiden University（莱顿大学）；Laboratory for Astrophysics, Leiden Observatory, Leiden University（莱顿大学莱登天文台天体物理实验室）；Max Planck Institut für Extraterrestrische Physik (MPE)（马克斯·普朗克地外物理学研究所）；European Southern Observatory（欧洲南方天文台）；INAF – Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）
