BANYAN. VII. Candidate YMG members from BASS

DOI

We present the results of a near-infrared (NIR) spectroscopic follow-up survey of 182 M4-L7 low-mass stars and brown dwarfs (BDs) from the BANYAN All-Sky Survey (BASS) for candidate members of nearby, young moving groups (YMGs). We confirm signs of low gravity for 42 new BD discoveries with estimated masses between 8 and 75M_Jup_ and identify previously unrecognized signs of low gravity for 24 known BDs. We refine the fraction of low-gravity dwarfs in the high-probability BASS sample to ~82%. We use this unique sample of 66 young BDs, supplemented with 22 young BDs from the literature, to construct new empirical NIR absolute magnitude and color sequences for low-gravity BDs. We show that low-resolution NIR spectroscopy alone cannot differentiate between the ages of YMGs younger than ~120Myr, and that the BT-Settl atmosphere models do not reproduce well the dust clouds in field or low-gravity L-type dwarfs. We obtain a spectroscopic confirmation of low gravity for 2MASS J14252798-3650229, which is a new ~27M_Jup_, L4 {gamma} bona fide member of AB Doradus. We identify a total of 19 new low-gravity candidate members of YMGs with estimated masses below 13M_Jup_, 7 of which have kinematically estimated distances within 40pc. These objects will be valuable benchmarks for a detailed atmospheric characterization of planetary-mass objects with the next generation of instruments. We find 16 strong candidate members of the Tucana-Horologium association with estimated masses between 12.5 and 14M_Jup_, a regime where our study was particularly sensitive. This would indicate that for this association there is at least one isolated object in this mass range for every 17.5_-5.0_^+6.6^ main-sequence stellar member, a number significantly higher than expected based on standard log-normal initial mass function, however, in the absence of radial velocity and parallax measurements for all of them, it is likely that this over-density is caused by a number of young interlopers from other associations.

Cone search capability for table J/ApJS/219/33/table8 (Physical parameters)

Cone search capability for table J/ApJS/219/33/table4 (Spectral classification, low gravity, and young moving group (YMG) membership)

Identifier
DOI http://doi.org/10.26093/cds/vizier.22190033
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJS/219/33
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/219/33
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/219/33
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJS/219/33
Provenance
Creator Gagne J.; Faherty J.K.; Cruz K.L.; Lafreniere D.; Doyon R.; Malo L.,Burgasser A.J.; Naud M.-E.; Artigau E.; Bouchard S.; Gizis J.E.; Albert L.
Publisher CDS
Publication Year 2015
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; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy