Primeval very low-mass stars and brown dwarfs: IV. New L subdwarfs, Gaia astrometry, population properties, and a blue brown dwarf binary
We present 27 new L subdwarfs and classify five of them as esdL and 22 as sdL. Our L subdwarf candidates were selected with the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey. Spectroscopic follow-up was carried out primarily with the OSIRIS spectrograph on the Gran Telescopio Canarias....
Saved in:
| Main Authors: | , |
|---|---|
| Format: | Article (Journal) Chapter/Article |
| Language: | English |
| Published: |
28 Aug 2018
|
| In: |
Arxiv
|
| Online Access: | Verlag, Volltext: http://arxiv.org/abs/1807.10560
|
| Author Notes: | Z.H. Zhang, M.C. Galvez-Ortiz, D.J. Pinfield, A.J. Burgasser, N. Lodieu, H.R.A. Jones, E.L. Martin, B. Burningham, D. Homeier, F. Allard, M.R. Zapatero Osorio, L.C. Smith, R.L. Smart, B. Lopez Marti, F. Marocco and R. Rebolo |
| Summary: | We present 27 new L subdwarfs and classify five of them as esdL and 22 as sdL. Our L subdwarf candidates were selected with the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey. Spectroscopic follow-up was carried out primarily with the OSIRIS spectrograph on the Gran Telescopio Canarias. Some of these new objects were followed up with the X-shooter instrument on the Very Large Telescope. We studied the photometric properties of the population of known L subdwarfs using colour-spectral type diagrams and colour-colour diagrams, by comparison with L dwarfs and main-sequence stars, and identified new colour spaces for L subdwarf selection/study in current and future surveys. We further discussed the brown dwarf transition-zone and the observational stellar/substellar boundary. We found that about one-third of 66 known L subdwarfs are substellar objects, with two-thirds being very low-mass stars. We also present the Hertzsprung-Russell diagrams, spectral type-absolute magnitude corrections, and tangential velocities of 20 known L subdwarfs observed by the Gaia astrometry satellite. One of our L subdwarf candidates, ULAS J233227.03+123452.0, is a mildly metal-poor spectroscopic binary brown dwarf: a ~L6p dwarf and a ~T4p dwarf. This binary is likely a thick disc member according to its kinematics. |
|---|---|
| Item Description: | Gesehen am 07.08.2020 |
| Physical Description: | Online Resource |