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Resolved Spectroscopy of M Dwarf/L Dwarf Binaries. I. DENIS J220002.05-303832.9AB

Adam J. Burgasser·Michael W. McElwain
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Abstract

We present the discovery of the common proper motion M9 + L0 binary DENIS J220002.05-303832.9AB, identified serendipitously with the SpeX near infrared imager/spectrograph. Spectral types are derived from resolved near infrared spectroscopy of the well-separated (1"09+/-0"06) components and comparison to equivalent data for M and L dwarf spectral standards. Physical association is deduced from the angular proximity of the sources, their common proper motion and their similar spectrophotometric distances (35+/-2 pc). The estimated distance of this pair implies a projected separation of 38+/-3 AU, wider than typical separations for other M dwarf/L dwarf binaries, but consistent with the maximum separation/total system mass trend previously identified by Burgasser et al. (2003). We discuss the DENIS 2200-3038AB system in context with other low mass binaries, and its role in studying dust formation processes and activity trends across the transition between the M and L dwarf spectral classes.

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Adam J. Burgasser, Michael W. McElwain. 2005-10-19. Resolved Spectroscopy of M Dwarf/L Dwarf Binaries. I. DENIS J220002.05-303832.9AB. https://doi.org/10.1086/499042

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