We present the discovery of the first L-type subdwarf , 2MASS J05325346+8246465 .
This object exhibits enhanced collision-induced H _ { 2 } absorption , resulting in blue NIR colors ( J - K _ { s } = 0.26 { \pm } 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 , \mu = 2 \farcs 60 \pm 0 \farcs 15 yr ^ { -1 } , and a substantial radial velocity , v _ { rad } = -195 { \pm } 11 km s ^ { -1 } , 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 \lesssim M \lesssim 0.085 M _ { \sun } for ages 10–15 Gyr and metallicities Z = 0.1 - 0.01 Z _ { \sun } .
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 .