The ρ Ophiuchi region revisited with Gaia EDR3

Natalie Grasser, Sebastian Ratzenböck, João Alves, Josefa Großschedl, Stefan Meingast, Catherine Zucker, Charles Lada, Alyssa Goodman, Marco Lombardi, John C. Forbes, Immanuel M. Bomze, Torsten Möller, Alvaro Hacar Gonzalez

Context. Young and embedded stellar populations are important probes of

the star formation process. Paradoxically, we have a better census of

nearby embedded young populations than the slightly more evolved

optically visible young populations. The high accuracy measurements and

all-sky coverage of Gaia data are about to change this situation. Aims.

This work aims to construct the most complete sample to date of YSOs in

the $\rho$ Oph region. Methods. We compile a catalog of 1114 Ophiuchus

YSOs from the literature and crossmatch it with the Gaia EDR3, Gaia-ESO

and APOGEE-2 surveys. We apply a multivariate classification algorithm

to this catalog to identify new, co-moving population candidates.

Results. We find 191 new high-fidelity YSO candidates in the Gaia EDR3

catalog belonging to the $\rho$ Oph region. The new sources appear to be

mainly Class III M-stars and substellar objects and are less extincted

than the known members. We find 28 previously unknown sources with

disks. The analysis of the proper motion distribution of the entire

sample reveals a well-defined bimodality, implying two distinct

populations sharing a similar 3D volume. The first population comprises

young stars' clusters around the $\rho$ Ophiuchi star and the main

Ophiuchus clouds (L1688, L1689, L1709). In contrast, the second

population is older ($\sim$ 10 Myr), dispersed, has a distinct proper

motion, and is possibly from the Upper Sco group. The two populations

are moving away from each other at about 4.1 km/s, and will no longer

overlap in about 4 Myr. Finally, we flag 17 sources in the literature as

impostors, which are sources that exhibit large deviations from the

average distance and proper motion properties of the $\rho$ Oph

population. Our results show the importance of accurate 3D space and

motion information for improved stellar population analysis. (Abridged)

Department of Astrophysics, Research Network Data Science, Department of Statistics and Operations Research, Research Group Visualization and Data Analysis
External organisation(s)
Harvard University, Harvard-Smithsonian Center for Astrophysics, Universitá degli Studi di Milano, Simons Foundation
Astronomy & Astrophysics
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103004 Astrophysics
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