Near-infrared spectroscopic characterisation of Gaia ultra-cool dwarf candidates; Spectral types and peculiarities
T. Ravinet, C. Reylé, N. Lagarde, A. Burgasser, R. L. Smart, W. H. Moya, F. Marocco, R. -D. Scholz, W. J. Cooper, K. L. Cruz, J. G. Fernández-Trincado, D. Homeier, L. M. Sarro
备注：
Based on observations made with the ESO New Technology Telescope at the La Silla Observatory under programme 106.214E.001 and 108.22G4.001. Accepted by A&A on the 30/01/2024
Context: The local census of very low-mass stars and brown dwarfs is crucial to improving our understanding of the stellar-substellar transition and their formation history. These objects, known as ultra-cool dwarfs (UCDs), are essential targets for searches of potentially habitable planets. However, their detection poses a challenge because of their low luminosity. The Gaia survey has identified numerous new UCD candidates thanks to its large survey and precise astrometry.
Aims: We aim to characterise 60 UCD candidates detected by Gaia in the solar neighbourhood with a spectroscopic follow-up to confirm that they are UCDs, as well as to identify peculiarities.
Methods: We acquired the near-infrared (NIR) spectra of 60 objects using the SOFI spectrograph between 0.93 and 2.5 microns (R$\sim600$). We identified their spectral types using a template-matching method. Their binarity is studied using astrometry and spectral features.
Results: We confirm that 60 objects in the sample have ultra-cool dwarf spectral types close to those expected from astrometry. Their NIR spectra reveal that seven objects could host an unresolved coolest companion and seven UCDs share the same proper motions as other stars. The characterisation of these UCDs is part of a coordinated effort to improve our understanding of the Solar neighbourhood.
Ariel stellar characterisation IV. Fundamental parameters of 18 hot stars in the Ariel mission candidate sample
Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）；Institute for Theoretical and Computation Physics, Graz University of Technology（格拉茨工业大学理论与计算物理研究所）；Department of Physics and Astronomy G. Galilei, University of Padova（帕多瓦大学伽利略物理学与天文学系）；INAF – Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；Departament d’Astronomia i Astrofísica, Universitat de València（瓦伦西亚大学天文与天体物理系）；INAF – Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；INAF – Osservatorio Astrofisico di Torino（意大利国家天体物理研究所都灵天文台）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Institute for Space Astrophysics and Planetology INAF-IAPS（意大利国家天体物理研究所空间天体物理与行星学研究所）；Department of Physics and Astronomy, University College London（伦敦大学学院物理学与天文学系）
Magnetic activity in cool stars: manifestations and relevance to exoplanets
Max-Planck-Institut für Sonnensystemforschung（马克斯·普朗克太阳系统研究所）；Centro de Rádio Astronomia e Astrofísica Mackenzie, Universidade Presbiteriana Mackenzie（麦肯齐射电天文学与天体物理学中心，麦肯齐长老会大学）；Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM（巴黎萨克雷大学，巴黎西岱大学，法国原子能和替代能源委员会，法国国家科学研究中心，天文信息与管理实验室）；Leibniz-Institut für Astrophysik Potsdam (AIP)（波茨坦莱布尼茨天体物理研究所）；HUN-REN Research Centre for Astronomy and Earth Sciences, Konkoly Observatory（匈牙利研究网络地球与天文学研究中心，孔科利天文台）；Instituto de Astronomía y Física del Espacio (IAFE, UBA-CONICET)（空间天体物理学与天体物理研究所）；The Catholic University of America（美国天主教大学）；The Hakubi Center for Advanced Research, Kyoto University（京都大学博雅教育研究中心）；Department of Physics, Kyoto University（京都大学物理学系）；University of Helsinki（赫尔辛基大学）
该项目的目的是对迄今发现的最冷的褐矮星Y矮星的光谱能量分布的特征做出贡献。我们在10.4米的加那利大望远镜（GTC）上使用OSIRIS（成像和低分辨率集成光谱学光学系统）仪器获得了6颗Y矮星和1颗T9+ Y 0双星的z波段远红外成像。我们在$z$波段探测到了已知的7颗Y矮星中的5颗，推断出它们的光学到红外颜色，并测量了它们的自行。我们发现Y 0矮星的z-J和z-H色的色散比T矮星的高。发现这种分散与H-w2相关。Y矮星的光红外色的高度分散和可能转向更蓝的颜色可能是不同厚度的硫化物云存在的结果，碱性的耗尽和/或重力效应。
Giant Planets and Eccentric Orbits Are Common Around Galactic Thick Disc Stars
Yale University（耶鲁大学）；The Observatories of the Carnegie Institution for Science（卡内基科学研究所天文台）；Universidad de Concepción（康塞普西翁大学）；Gemini Observatory（吉米尼天文台）；NSF’s NOIRLab（美国国家光学红外天文实验室）；Pomona College（波莫纳学院）
K 1-6 is a photoionised ISM nebula shaped by a fast-moving hot white dwarf in a triple system
Astronomical Institute of Charles University（查理大学天文研究所）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Departamento de Astrofísica, Universidad de La Laguna（拉帕尔马拉古纳大学天体物理学系）；European Southern Observatory（欧洲南方天文台）；Landessternwarte Heidelberg, Zentrum für Astronomie, Ruprecht-Karls-Universität（海德堡州立天文台，海德堡大学天文学中心）
Degenerate interpretations of O$_3$ spectral features in exoplanet atmosphere observations due to stellar UV uncertainties: a 3D case study with TRAPPIST-1e
