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An Optical and Near Infrared Search for Brown Dwarfs in the Pleiades Cluster

C. Nagashima·P. D. Dobbie·T. Nagayama·Y. Nakajima·T. Nagata·M. Tamura·T. Nakajima·K. Sugitani·H. Nakaya·S. T. Hodgkin·A. J. Pickles·S. Sato
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Abstract

We have carried out a brown dwarf search over an area of 14' x 23' near the central portion of the Pleiades open cluster in five optical and near infrared bands (i', Z, J, H, Ks) with 10 sigma detection limits of i' = 22.0, J = 20.0 and Ks = 18.5 mag. The surveyed area has large extinction in excess of Av = 3 in the Pleiades region. We detected four new brown dwarf candidates from the colour-colour (J-K, i'-J) and the colour-magnitude (J, i'-K) diagrams. We estimated their masses as 0.046 Msun down to 0.028 Msun. The least massive one is estimated to have a mass smaller than Roque 25 or int-pl-IZ-69, and maybe the lowest mass object found so far in the Pleiades cluster.

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C. Nagashima, P. D. Dobbie, T. Nagayama, Y. Nakajima, T. Nagata, M. Tamura, T. Nakajima, K. Sugitani, H. Nakaya, S. T. Hodgkin, A. J. Pickles, S. Sato. 2003-05-10. An Optical and Near Infrared Search for Brown Dwarfs in the Pleiades Cluster. https://doi.org/10.1046/j.1365-8711.2003.06766.x

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