Pre-main sequence stars in Scorpius OB1

DOI

The low-mass members of OB associations, expected to be a major component of their total population, are in most cases poorly studied because of the difficulty of selecting these faint stars in crowded sky regions. Our knowledge of many OB associations relies on only a relatively small number of massive members. We study here the Sco OB1 association, with the aim of a better characterization of its properties, such as global size and shape, member clusters and their morphology, age and formation history, and total mass. We use deep optical and near-infrared (NIR) photometry from the VPHAS+ and VVV surveys, over a wide area (2.6{deg}x2.6{deg}), complemented by Spitzer infrared (IR) data, and Chandra and XMM-Newton X-ray data. A new technique is developed to find clusters of pre-main sequence M-type stars using suitable color-color diagrams, complementing existing selection techniques using narrow-band H{alpha} photometry or NIR and ultraviolet (UV) excesses, and X-ray data. We find a large population of approximately 4000 candidate low-mass Sco OB1 members whose spatial properties correlate well with those of H{alpha}-emission, NIR-excess, UV-excess, and X-ray detected members, and unresolved X-ray emission. The low-mass population is spread among several interconnected subgroups: they coincide with the HII regions G345.45+1.50 and IC4628, and the rich clusters NGC 6231 and Trumpler 24, with an additional subcluster intermediate between these two. The total mass of Sco OB1 is estimated to be ~8500M_{sun}_. Indication of a sequence of star-formation events is found, from South (NGC 6231) to North (G345.45+1.50). We suggest that the diluted appearance of Trumpler 24 indicates that the cluster is now dissolving into the field, and that tidal stripping by NGC 6231 nearby contributes to the process.

Cone search capability for table J/A+A/615/A148/tableb2 (XMM-Newton EPIC X-ray sources in Trumpler 24)

Cone search capability for table J/A+A/615/A148/tableb3 (Optical/NIR photometry for M stars and stars with UV/IR/H{alpha} excess)

Cone search capability for table J/A+A/615/A148/tableb1 (Chandra ACIS-I X-ray sources in G345.45+1.50)

Identifier
DOI http://doi.org/10.26093/cds/vizier.36150148
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/A+A/615/A148
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/615/A148
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/615/A148
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/A+A/615/A148
Provenance
Creator Damiani F.
Publisher CDS
Publication Year 2018
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Cosmology; Natural Sciences; Physics; Stellar Astronomy