Brown Dwarfs among newly detected high-proper motion stars?
Abstract
In order to carry out a new high-proper motion survey of the southern sky (Scholz et al. 1999ab), the re-reduction of APM measurements of UKST plates covering more than 3000 square degrees has now been completed. The main aim of the survey is to extend the existing proper motion catalogues (with mu>0.3arcsec/yr) to fainter magnitudes. For the faintest objects (R > 18), we have carried out follow-up optical spectroscopy at the SAAO and Keck, classifying two groups of objects: cool white dwarfs and late-type M dwarfs and subdwarfs. Among the latter group we have discovered 4 very late-type (>dM6.5) M dwarfs and one very late-type extreme subdwarf (esdM6). Since the extremely red objects in the high-proper motion sample are as red and as dim as the free-floating brown dwarf Kelu 1, many of these sources are also potential brown dwarf candidates. A more detailed investigation of the nature of these sources is now in progress, using VLT optical and near-infrared spectroscopy.
Scholz R.-D., Irwin M., Ibata R., Jahreiß H., Malkov O.Yu., 1999a, A&A, submitted Scholz R.-D., Irwin M., Schweitzer A., Ibata R., 1999b, A&A, 345, L55- Publication:
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Astronomische Gesellschaft Abstract Series
- Pub Date:
- 1999
- Bibcode:
- 1999AGAb...15...21S
- Keywords:
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- Proper-Motion Stars: Brown Dwarfs