Binary stars in Upper Scorpius

DOI

To address the statistics of binary stars in the 8 Myr old Upper Scorpius (USco) star formation region, we conducted a speckle interferometric survey of 614 association members more massive than 0.4 M_{sun}_ (spectral types earlier than M3V) based on the list of Luhman et al. (2018, J/AJ/156/271). We resolved 187 pairs, 55 of which are new discoveries. Also using the published data and the Gaia DR2 (Cat. I/345), a catalog of 250 physical binaries was produced. We carefully estimated detection limits for each target and studied binary statistics in the separation range from 0.06" to 20" (9-2800 au), as well as clustering at larger separations. The frequency of companions with mass ratios q>0.3 in this separation range is 0.33+/-0.04 and 0.35+/-0.04 for early M- and solar-type stars, respectively, larger by 1.62+/-0.22 and 1.39+/-0.18 times compared to field stars of similar masses. The excess is produced mostly by pairs closer than 100 au. At separations from 100 to 10^4^ au, the separation distribution and companion fraction resemble those of solar-type stars in the field. However, unlike in the field, we see a relative deficit of equal-mass binaries at separations of ~500 au, compared to smaller and larger separations. The distribution of q depends on the separation, with a preference of larger q and a larger fraction of twins with q>0.95 at smaller separations. The binary population of USco differs from binaries in the field in several ways and suggests that binary statistics is not universal.

Cone search capability for table J/AJ/159/15/table1 (Filtered Luhman's sample)

Identifier
DOI http://doi.org/10.26093/cds/vizier.51590015
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/AJ/159/15
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/159/15
Related Identifier https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/159/15
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/AJ/159/15
Provenance
Creator Tokovinin A.; Briceno C.
Publisher CDS
Publication Year 2020
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; Galactic and extragalactic Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy