Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Primeval very low-mass stars and brown dwarfs. I. Six new L subdwarfs,
  classification and atmospheric properties   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, ULAS J124425.75+102439.3). We examined the spectral types
and metallicity subclasses classification of known L subdwarfs. We summarised
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 K and
2700 K, which are higher than similarly-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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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: econ
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph