dc.contributor.author | Zhang, Z. H. | |
dc.contributor.author | Homeier, D. | |
dc.contributor.author | Pinfield, David | |
dc.contributor.author | Lodieu, N. | |
dc.contributor.author | Jones, Hugh | |
dc.contributor.author | Allard, F. | |
dc.contributor.author | Pavlenko, Ya V. | |
dc.date.accessioned | 2017-06-05T16:57:00Z | |
dc.date.available | 2017-06-05T16:57:00Z | |
dc.date.issued | 2017-06-01 | |
dc.identifier.citation | Zhang , Z H , Homeier , D , Pinfield , D , Lodieu , N , Jones , H , Allard , F & Pavlenko , Y V 2017 , ' Primeval very low-mass stars and brown dwarfs -- II. The most metal-poor substellar object ' , Monthly Notices of the Royal Astronomical Society , vol. 468 , no. 1 , pp. 261-271 . https://doi.org/10.1093/mnras/stx350 | |
dc.identifier.issn | 0035-8711 | |
dc.identifier.other | ArXiv: http://arxiv.org/abs/1702.02001v1 | |
dc.identifier.uri | http://hdl.handle.net/2299/18286 | |
dc.description | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. | |
dc.description.abstract | SDSS J010448.46+153501.8 has previously been classified as an sdM9.5 subdwarf. However, it's very blue J-K colour (-0.15+/-0.17) suggests a much lower metallicity compared to normal sdM9.5 subdwarfs. Here we re-classify this object as a usdL1.5 subdwarf based on a new optical and near-infrared spectrum obtained with X-shooter on the Very Large Telescope. Spectral fitting with BT-Settl models leads to Teff = 2450+/-150 K, [Fe/H] = -2.4+/-0.2 and log g = 5.5+/-0.25. We estimate a mass for SDSS J010448.46+153501.8 of 0.0855+/-0.0015 M_{\sun} which is just below the hydrogen-burning minimum mass at [Fe/H] = -2.4 (\sim0.0875 M_{\sun}) according to evolutionary models. Our analysis thus shows SDSS J0104+15 to be the most metal-poor and highest mass substellar object known to date. We found that SDSS J010448.46+153501.8 is joined by another five known L subdwarfs (2MASS J05325346+8246465, 2MASS J06164006-6407194, SDSS J125637.16-022452.2, ULAS J151913.03-000030.0, and 2MASS J16262034+3925190) in a `halo brown dwarf transition zone' in the Teff-[Fe/H] plane, which represents a narrow mass range in which unsteady nuclear fusion occurs. This halo brown dwarf transition zone forms a `substellar subdwarf gap' for mid L to early T types. | en |
dc.format.extent | 11 | |
dc.format.extent | 2746906 | |
dc.language.iso | eng | |
dc.relation.ispartof | Monthly Notices of the Royal Astronomical Society | |
dc.subject | brown dwarfs | |
dc.subject | stars: chemically peculiar | |
dc.subject | stars: individual: SDSS J010448 + 153501.8 | |
dc.subject | stars: low-mass | |
dc.subject | stars: Population II | |
dc.subject | subdwars | |
dc.title | Primeval very low-mass stars and brown dwarfs -- II. The most metal-poor substellar object | en |
dc.contributor.institution | School of Physics, Astronomy and Mathematics | |
dc.contributor.institution | Centre for Astrophysics Research (CAR) | |
dc.description.status | Peer reviewed | |
rioxxterms.versionofrecord | 10.1093/mnras/stx350 | |
rioxxterms.type | Journal Article/Review | |
herts.preservation.rarelyaccessed | true | |