Trigonometric parallax astrometry and BVI photometry are presented for two late-type subdwarf candidates , LSR1425+71 ( sdM8.0 ) and LSR1610 - 00 ( sd ? M6pec ) .
For the former we measure an absolute parallax of 13.37 \pm 0.51 mas yielding M _ { V } = 15.25 \pm 0.09 .
The astrometry for LSR1610 - 00 shows that this object is an astrometric binary with a period of 1.66 \pm 0.01 yr .
The photocentric orbit is derived from the data ; it has a moderate eccentricity ( e \approx 0.44 \pm 0.02 ) and a semi-major axis of 0.28 \pm 0.01 AU based on our measured absolute parallax of 31.02 \pm 0.26 mas .
Our radial velocity measure of - 108.1 \pm 1.6 km s ^ { -1 } for LSR1610 - 00 at epoch 2006.179 , when coupled with the observation of - 95 \pm 1 km s ^ { -1 } at epoch 2005.167 by Reiners & Basri , indicates a systemic radial velocity of - 101 \pm 1 km s ^ { -1 } for the LSR1610 - 00AB pair .
The galactic velocity components for LSR1425+71 and LSR1610 - 00AB – ( U , V , W ) = ( 84 \pm 6 , - 202 \pm 13 , 66 \pm 14 ) km s ^ { -1 } and ( U , V , W ) = ( 36 \pm 2 , - 232 \pm 2 , - 61 \pm 2 ) km s ^ { -1 } , respectively .
For both stars , the velocities are characteristic of halo population kinematics .
However , modelling shows that both stars have orbits around the galaxy with high eccentricity that pass remarkably close to the galactic center .
LSR1425+71 has a luminosity and colors consistent with its metal-poor subdwarf spectral classification , while LSR1610 - 00 has a luminosity and most colors indicative of being only mildly metal-poor , plus a uniquely red B - V color .
The companion to LSR1610 - 00 must be a low-mass , substellar brown dwarf .
We speculate on the paradoxical nature of LSR1610 - 00 and possible sources of its peculiarities .