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A deep photometric survey of the eta Chamaeleontis cluster down to the brown dwarf - planet boundary

A-Ran Lyo·Inseok Song·Warrick A. Lawson·M. S. Bessell·B. Zuckerman
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Abstract

We report the outcome of the deep optical/infrared photometric survey of the central region (33 X 33 arcmin or 0.9 pc^2) of the eta Chamaeleontis pre-main sequence star cluster. The completeness limits of the photometry are I = 19.1, J = 18.2 and H = 17.6; faint enough to reveal low mass members down to the brown dwarf and planet boundary of ~ 13 M_Jup. We found no such low mass members in this region. Our result combined with a previous shallower (I = 17) but larger area survey indicates that low mass objects (0.013 < M/M(solar mass) < 0.075) either were not created in the eta Cha cluster or were lost due to the early dynamical history of the cluster and ejected to outside the surveyed areas.

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A-Ran Lyo, Inseok Song, Warrick A. Lawson, M. S. Bessell, B. Zuckerman. 2006-04-04. A deep photometric survey of the eta Chamaeleontis cluster down to the brown dwarf - planet boundary. https://doi.org/10.1111/j.1365-2966.2006.10232.x

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