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: email@example.com
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
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.