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Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2017

Primeval very low-mass stars and brown dwarfs - I. Six new L subdwarfs, classification and atmospheric properties

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Z. H. Zhang
  • Function : Author
D. J. Pinfield
  • Function : Author
M. C. Gálvez-Ortiz
  • Function : Author
B. Burningham
  • Function : Author
N. Lodieu
  • Function : Author
F. Marocco
  • Function : Author
A. J. Burgasser
  • Function : Author
A. C. Day-Jones
  • Function : Author
H. R. A. Jones
  • Function : Author
D. Homeier
  • Function : Author
J. Gomes
  • Function : Author
R. L. Smart
  • Function : Author

Abstract

We have conducted a search for L subdwarf candidates within the photometric catalogues of the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey. Six of our candidates are confirmed as L subdwarfs spectroscopically at optical and/or near-infrared wavelengths. We also present new optical spectra of three previously known L subdwarfs (WISEA J001450.17-083823.4, 2MASS J00412179+3547133, and ULAS J124425.75+102439.3). We examined the spectral type and metallicity classification of subclasses of known L subdwarfs. We summarized the spectroscopic properties of L subdwarfs with different spectral types and subclasses. We classify these new L subdwarfs by comparing their spectra to known L subdwarfs and L dwarf standards. We estimate temperatures and metallicities of 22 late-type M and L subdwarfs by comparing their spectra to BT-Settl models. We find that L subdwarfs have temperatures between 1500 and 2700 K, which are higher than similar-typed L dwarfs by around 100-400 K depending on different subclasses and subtypes. We constrained the metallicity ranges of subclasses of M, L, and T subdwarfs. We also discussed the spectral-type and absolute magnitude relationships for L and T subdwarfs.
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insu-03710632 , version 1 (01-07-2022)

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Z. H. Zhang, D. J. Pinfield, M. C. Gálvez-Ortiz, B. Burningham, N. Lodieu, et al.. Primeval very low-mass stars and brown dwarfs - I. Six new L subdwarfs, classification and atmospheric properties. Monthly Notices of the Royal Astronomical Society, 2017, 464, pp.3040-3059. ⟨10.1093/mnras/stw2438⟩. ⟨insu-03710632⟩
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