With the purpose of performing a homogeneous determination of elemental abundances for members of the Lupus T association, we analyzed three chemical elements: lithium, iron, and barium. The aims were: to derive the Li abundance for ~90% of known class II stars in the Lupus I, II, III, IV clouds; to perform chemical tagging of a region where few Fe abundance measurements have been obtained in the past, and no determination of the Ba content has been done up to now. We also investigated possible Ba enhancement, as this element has become increasingly interesting in the last years following the evidence of Ba over-abundance in young clusters, the origin of which is still unknown. Using X-shooter@VLT, we analyzed the spectra of 89 cluster members, both class II and III stars. We measured the strength of the Li line and derived the abundance of this element through equivalent width measurements and curves of growth. For six class II stars we also measured the Fe and Ba abundances using the spectral synthesis and the code MOOG. The veiling contribution was taken into account for all three elements. We find a dispersion in the strength of the Li line at low Teff and identify three targets with severe Li depletion. The nuclear age inferred for these highly Li-depleted stars is around 15 Myr, which exceeds the isochronal one. As in other star-forming regions, no metal-rich members are found in Lupus, giving support to a recent hypothesis that the Fe abundance distribution of most of the nearby young regions could be the result of a common and widespread star formation episode involving the Galactic thin disk. We find that Ba is over-abundant by ~0.7 dex with respect to the Sun. Since current theoretical models cannot reproduce this Ba abundance pattern, we investigated whether this unusually large Ba content might be related to effects due to stellar parameters, stellar activity, and accretion.
New members of the Lupus I cloud based on Gaia astrometry Physical and accretion properties from X-Shooter spectra
我们表征12个年轻的恒星物体（YSO）位于狼疮I区域，空间上重叠的上半人马座狼疮（UCL）的亚恒星协会。本研究的目的是了解是否狼疮I云有更多的成员比已经声称到目前为止在文献中，并获得更深入的了解该地区的全球属性。我们使用盖亚DR 2目录选择了我们的目标，基于它们与狼疮I真正成员一致的运动学特性。在X射手观察到的12个YSO样本中，我们确定了10个狼疮I成员。由于技术问题，我们无法确定两个目标的成员状态，即Gaia DR 2 6014269268967059840和2 MASS J15361110-3444473。我们发现我们的四个目标是吸积体，其中2 MASS J15551027-3455045，质量约为0.03 M_Sun，是迄今为止狼疮复合体中质量最小的吸积体之一。我们的几个目标（包括吸积体）是相对于狼疮I的主灯丝在原位和离云形成的，因此，我们的研究可能暗示在狼疮I主灯丝周围有扩散的M-矮星种群。在这种情况下，我们想强调的是，我们与盖亚目录的运动学分析在识别狼疮I云的新成员方面发挥了关键作用。
PENELLOPE: IX. Lithium, iron and barium elemental abundances in eight nearby young clusters
INAF-Osservatorio Astronomico di Roma（罗马天文台）；INAF-Osservatorio Astrofisico di Catania（卡塔尼亚天文台）；European Southern Observatory（欧洲南方天文台）；INAF-Osservatorio Astronomico di Capodimonte（卡波迪蒙特天文台）；Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences（孔科利天文台，匈牙利研究网络天文学与地球科学研究中心）；Institute of Physics and Astronomy, ELTE Eötvös Loránd University（罗兰大学物理与天文学研究所）；Institute for Astronomy (IfA), University of Vienna（维也纳大学天体物理研究所）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；ASI, Italian Space Agency（意大利航天局）
The He I $λ$10830 $Å$ line as a probe of winds and accretion in young stars in Lupus and Upper Scorpius
He I 1微米线是一条高激发线，它使我们能够探测原恒星盘的最内部区域，并追踪吸积和流出的物质。我们使用X-Shooter观测的样本107年轻的恒星在狼（1-3百万年）和上天蝎座（5-10百万年）恒星形成区域的线属性之间的相关性，以及磁盘的倾斜度和吸积光度搜索。我们在样本中确定了八种不同的轮廓类型。我们将高斯曲线拟合到线特征以测量在吸收中跟踪的最大速度、线特征的半高宽（FWHM）和特征的高斯面积。我们将样本中每种配置文件类型的比例与之前在金牛座的研究进行比较。我们发现金牛座和狼疮之间的P天鹅座和逆P天鹅座配置文件的比例显着变化，狼疮和上天蝎座之间的排放量的唯一和组合配置文件类型的数量。我们发现，蓝移的吸收功能出现较少的蓝移在磁盘倾角接近边缘上，但没有这样的趋势与倾角观察只有红移功能的来源。在具有强烈蓝移特征的源中观察到更高的吸积速率，随着在两个区域观察到的每种剖面类型比例的变化，表明较年轻的源可能驱动更强的喷流或风。总的来说，我们观察到的比例的变化，每一个配置文件类型和线的属性，这表明和演化的吸积和喷射签名随着时间的推移，并与源属性。这些结果证实了过去的工作和模型的He I线，但对于一个更大的样本和多个恒星形成区。这项工作突出了He I线作为圆盘最内部区域气体探测器的力量。
X-Shooter survey of disk accretion in Upper Scorpius II. A lack of correlation between accretion rates and disk properties
University College Dublin (UCD)（都柏林大学学院）；European Southern Observatory（欧洲南方天文台）；School of Cosmic Physics, Dublin Institute for Advanced Studies（都柏林高等研究院宇宙物理学院）；Department of Physics, Maynooth University（梅努斯大学物理系）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；Institue of Astronomy, University of Cambridge（剑桥大学天文研究所）；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）；School of Physics, Trinity College Dublin, the University of Dublin（都柏林三一学院物理学院，都柏林大学）；Joint ALMA Observatory（ALMA联合天文台）；Dipartimento di Fisica, Università degli Studi di Milano（米兰大学物理系）
X-shooter survey Across Regions and Ages to probe Disk Evolution (ARADE): Accretion properties in Orion A and their relation with disk masses
European Southern Observatory（欧洲南方天文台）；Trinity College Dublin, the University of Dublin（都柏林三一学院，都柏林大学）；Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）；Istituto Nazionale di Astrofisica (INAF)—Osservatorio Astronomico di Palermo（意大利国家天体物理研究所（INAF）—巴勒莫天文台）；Maynooth University Department of Physics, National University of Ireland Maynooth（梅努斯大学物理系，爱尔兰国立大学梅努斯分校）；University College Dublin（都柏林大学学院）；Ludwig-Maximilians-Universität München（慕尼黑大学）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理学研究所）
PENELLOPE VII: Revisiting empirical relations to measure accretion luminosity
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）；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）；European Southern Observatory（欧洲南方天文台）；Boston University（波士顿大学）；Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences（孔科利天文台，匈牙利研究与教育网络天文学与地球科学研究中心）；University of Vienna（维也纳大学）；SETI Institute（搜寻地外文明研究所）；Observatoire de Paris - PSL University（巴黎天文台-PSL大学）；Univ. grenoble Alpes（格勒诺布尔阿尔卑斯大学）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Università degli Studi di Milano（米兰大学）；Leiden University（莱顿大学）
