New members of the Lupus I cloud based on Gaia astrometry Physical and accretion properties from X-Shooter spectra

TL;DR

This study uses Gaia astrometry and X-Shooter spectra to identify new young stellar objects in Lupus I, revealing more members and providing insights into their properties and formation environments.

Contribution

The paper demonstrates the effectiveness of Gaia data combined with spectroscopic analysis to discover new Lupus I members and characterize their accretion and formation properties.

Findings

Identified 10 new Lupus I members among 12 YSOs observed.

Discovered a very low-mass accretor (~0.03 M_Sun) in Lupus I.

Found evidence of in-situ and off-cloud star formation in Lupus I.

Abstract

We characterize twelve young stellar objects (YSOs) located in the Lupus I region, spatially overlapping with the Upper Centaurus Lupus (UCL) sub-stellar association. The aim of this study is to understand whether the Lupus I cloud has more members than what has been claimed so far in the literature and gain a deeper insight into the global properties of the region. We selected our targets using Gaia DR2 catalog, based on their consistent kinematic properties with the Lupus I bona fide members. In our sample of twelve YSOs observed by X-Shooter, we identified ten Lupus I members. We could not determine the membership status of two of our targets, namely Gaia DR2 6014269268967059840 and 2MASS J15361110-3444473 due to technical issues. We found out that four of our targets are accretors, among them 2MASS J15551027-3455045, with a mass of ~0.03 M_Sun, is one of the least massive accretors in the Lupus complex to date. Several of our targets (including accretors) are formed in-situ and off-cloud with respect to the main filaments of Lupus I, hence, our study may hint that there are diffused populations of M-dwarfs around Lupus I main filaments. In this context, we would like to emphasize that our kinematic analysis with Gaia catalogs played a key role in identifying the new members of the Lupus I cloud.