Volume 440, Number 3, September IV 2005
|Page(s)||1061 - 1078|
|Section||Stellar structure and evolution|
|Published online||05 September 2005|
Spectroscopic classification of red high proper motion objects in the Southern Sky
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
2 Department of Physics & Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK e-mail: firstname.lastname@example.org
3 School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
4 Observatoire de Strasbourg, 11 rue de l'Université, 67000 Strasbourg, France
5 Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
Accepted: 6 June 2005
We present the results of spectroscopic follow-up observations for a sample of 71 red objects with high proper motions in the range 0.08-1.14 arcsec yr-1 as detected using APM and SSS measurements of multi-epoch photographic Schmidt plates. Red objects were selected by combining the photographic BJRI magnitudes with 2MASS near-infrared JHKs magnitudes. Some 50 of the 71 spectroscopically classified objects turn out to be late-type (>M6) dwarfs and in more detail, the sample includes 35 ultracool dwarfs with spectral types between M8 and L2, some previously reported, as well as five M-type subdwarfs, including a cool esdM6 object, SSSPM J0500-5406. Distance estimates based on the spectral types and 2MASS J magnitudes place almost all of the late-type (>M6) dwarfs within 50 pc, with 25 objects located inside the 25 pc limit of the catalogue of nearby stars. Most of the early-type M dwarfs are located at larger distances of 100-200 pc, suggesting halo kinematics for some of them. All objects with Hα equivalent widths larger than 10 Å have relatively small tangential velocities (<50 km s-1). Finally, some late-type but blue objects are candidate binaries.
Key words: surveys / stars: kinematics / stars: late-type / stars: low-mass, brown dwarfs / techniques: photometric / techniques: spectroscopic
© ESO, 2005
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