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| Paper: |
Peculiar L Dwarfs from the SDSS – 2MASS Crossmatch |
| Volume: |
448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun |
| Page: |
1351 |
| Authors: |
Geissler, K.; Metchev, S.; Kirkpatrick, J. D.; Berriman, G. B.; Looper, D. |
| Abstract: |
We report the discovery of six peculiar L dwarfs found in a positional and color cross-match of the SDSS DR1 and the 2MASS PSC databases. The cross-match was designed to identify objects with extremely red z-J colors (>2.75 mag), usually T dwarfs. Initial results, including the discovery of two new T dwarfs and 22 L dwarf candidates in SDSS DR1, were reported in Metchev et al. (2008). We present the spectroscopic classification of 17 additional candidates, 15 of which are confirmed as bona-fide L dwarfs in Geissler et al. (submitted). Four of these have peculiar spectral energy distributions, either significantly bluer or redder than the corresponding spectral standards. The unusual properties of peculiar L dwarfs are generally attributed to high or low surface gravity, reduced or enhanced metallicity or unusual cloud properties. In some cases binarity may explain the observed peculiarities. Spectral fitting of the L dwarf sample shows that five dwarfs are best fitted by composite spectra, suggesting that they may be unresolved binaries. Altogether, the full SDSS DR1 / 2MASS PSC cross-match produced 26 confirmed L dwarfs, among which six are peculiar, including one likely composite systems. Here we present spectra of three of the peculiar L dwarfs and four candidate binaries identified in the SDSS DR1 / 2MASS PSC cross-match. |
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