SIMBAD references

2003ApJ...592.1186B - Astrophys. J., 592, 1186-1192 (2003/August-1)

The first substellar subdwarf? Discovery of a metal-poor L dwarf with halo kinematics.

BURGASSER A.J., KIRKPATRICK J.D., BURROWS A., LIEBERT J., REID I.N., GIZIS J.E., McGOVERN M.R., PRATO L. and McLEAN I.S.

Abstract (from CDS):

We present the discovery of the first L-type subdwarf, 2MASS J05325346+8246465. This object exhibits enhanced collision-induced H2absorption, resulting in blue near-infrared (NIR) colors (J-Ks=0.26±0.16). In addition, strong hydride bands in the red optical and NIR, weak TiO absorption, and an optical/J-band spectral morphology similar to the L7 DENIS 0205-1159AB imply a cool, metal-deficient atmosphere. We find that 2MASS 0532+8246 has both a high proper motion, µ=2".60±0".15yr–1, and a substantial radial velocity, vrad=-195±11 km/s, and its probable proximity to the Sun (d=10-30 pc) is consistent with halo membership. Comparison to subsolar-metallicity evolutionary models strongly suggests that 2MASS 0532+8246 is substellar, with a mass of 0.077≲M≲0.085Mfor ages 10-15 Gyr and metallicities Z=0.1-0.01Z. The discovery of this object clearly indicates that star formation occurred below the hydrogen burning mass limit at early times, consistent with prior results indicating a flat or slightly rising mass function for the lowest mass stellar subdwarfs. Furthermore, 2MASS 0532+8246 serves as a prototype for a new spectral class of subdwarfs, additional examples of which could be found in NIR proper-motion surveys.

Abstract Copyright:

Journal keyword(s): Infrared: Stars - Galaxy: Solar Neighborhood - Stars: Chemically Peculiar - Stars: Individual: Alphanumeric: 2MASS J05325346+8246465 - Stars: Low-Mass, Brown Dwarfs - Stars: Subdwarfs

Simbad objects: 12

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