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The first wide ultracool binary dwarf in the field: DENIS-J055146.0-443412.2 (M8.5 + L0)

M. Billeres·X. Delfosse·J. -L. Beuzit·T. Forveille·L. Marchal·E. L. Martin
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Abstract

We present observations of a new very low mass field binary, discovered during an infrared imaging survey of 250 DENIS L and very late-M dwarfs. DENIS-J055146.0-443412.2 is an M8.5+L0 pair, with a physical separation of over 200 AU. This makes it the widest very low mass binary known in the field, by an order of magnitude. Such a system is fragile, and it would not have survived a close encounter with a third body. Its existence demonstrate that some very low mass stars/brown dwarfs form without ejection from a multiple system, or any other strong dynamical interaction.

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M. Billeres, X. Delfosse, J. -L. Beuzit, T. Forveille, L. Marchal, E. L. Martin. 2005-08-04. The first wide ultracool binary dwarf in the field: DENIS-J055146.0-443412.2 (M8.5 + L0). https://doi.org/10.1051/0004-6361%3A200500167

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