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arXiv · 1309.0503

A Search for L/T Transition Dwarfs With Pan-STARRS1 and WISE: Discovery of Seven Nearby Objects Including Two Candidate Spectroscopic Variables

William M. J. Best·Michael C. Liu·Eugene A. Magnier·Kimberly M. Aller·Niall R. Deacon·Trent J. Dupuy·Joshua Redstone·W. S. Burgett·K. C. Chambers·K. W. Hodapp·N. Kaiser·R. -P. Kudritzki·J. S. Morgan·P. A. Price·J. L. Tonry·R. J. Wainscoat
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Abstract

We present initial results from a wide-field (30,000 deg^2) search for L/T transition brown dwarfs within 25 pc using the Pan-STARRS1 and WISE surveys. Previous large-area searches have been incomplete for L/T transition dwarfs, because these objects are faint in optical bands and have near-infrared colors that are difficult to distinguish from background stars. To overcome these obstacles, we have cross-matched the Pan-STARRS1 (optical) and WISE (mid-IR) catalogs to produce a unique multi-wavelength database for finding ultracool dwarfs. As part of our initial discoveries, we have identified seven brown dwarfs in the L/T transition within 9-15 pc of the Sun. The L9.5 dwarf PSO J140.2308+45.6487 and the T1.5 dwarf PSO J307.6784+07.8263 (both independently discovered by Mace et al. 2013) show possible spectroscopic variability at the Y- and J-bands. Two more objects in our sample show evidence of photometric J-band variability, and two others are candidate unresolved binaries based on their spectra. We expect our full search to yield a well-defined, volume-limited sample of L/T transition dwarfs that will include many new targets for study of this complex regime. PSO J307.6784+07.8263 in particular may be an excellent candidate for in-depth study of variability, given its brightness (J = 14.2 mag) and proximity (11 pc).

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William M. J. Best, Michael C. Liu, Eugene A. Magnier, Kimberly M. Aller, Niall R. Deacon, Trent J. Dupuy, Joshua Redstone, W. S. Burgett, K. C. Chambers, K. W. Hodapp, N. Kaiser, R. -P. Kudritzki, J. S. Morgan, P. A. Price, J. L. Tonry, R. J. Wainscoat. 2013-09-02. A Search for L/T Transition Dwarfs With Pan-STARRS1 and WISE: Discovery of Seven Nearby Objects Including Two Candidate Spectroscopic Variables. https://doi.org/10.1088/0004-637x/777/2/84

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