Distance estimates based on low-resolution spectroscopy and Two Micron All Sky Survey ( 2MASS ) J magnitudes are presented for a large sample of 322 nearby candidates from Luyten ’ s NLTT catalogue .
Mainly relatively bright ( typically 7 < K _ { \mathrm { s } } < 11 ) and red high proper motion stars have been selected according to their 2MASS magnitudes and optical-to-infrared colours ( +1 < R - K _ { \mathrm { s } } < +7 ) .
Some LHS stars previously lacking spectroscopy have also been included .
We have classified the majority of the objects as early-M dwarfs ( M2-M5 ) .
More than 70 % of our targets turned out to lie within the 25 pc horizon of the catalogue of nearby stars , with 50 objects placed within 15 pc and 8 objects being closer than 10 pc .
Three objects in the 10 pc sample have no previously published spectral type : LP 876-10 ( M4 ) , LP 870-65 ( M4.5 ) , and LP 869-26 ( M5 ) .
A large fraction of the objects in our sample ( 57 % ) have independent distance estimates , mainly by the recent efforts of Reid and collaborators .
Our distance determinations are generally in good agreement with theirs .
11 rather distant ( d > 100 pc ) objects have also been identified , including a probable halo , but relatively hot ( T _ { eff } \sim 13000 K ) white dwarf ( LHS 1200 ) and 10 red dwarfs with extremely large tangential velocities ( 250 < v _ { \mathrm { t } } < 1150 km/s ) .
Altogether , there are 11 red dwarfs ( including one within 70 pc ) with tangential velocities larger than about 250 km/s .
All these objects are suspected to be in fact subdwarfs , if so , their distances would be only about half of our original estimates .
The three most extreme objects in that respect are the K and early M dwarfs LP 323-168 , LHS 5343 and LP 552-21 with corrected distances between 180 pc and 400 pc and resulting tangential velocities still larger than about 400 km/s .