Proper motion L and T dwarf candidate members of the Pleiades |
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| Authors: | S L Casewell P D Dobbie S T Hodgkin E Moraux R F Jameson N C Hambly J Irwin N Lodieu |
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| Institution: | Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH;Anglo-Australian Observatory, PO Box 296, Epping, NSW 1710, Australia;CASU, Institute of Astronomy,University of Cambridge, Maddingley Road, Cambridge CB3 0HA;Laboratoire d'Astrophysique, Observatoire de Grenoble, UniversitéJoseph Fourier, BP 53, 38041 Grenoble Cedex 9, France;Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, School of Physics, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ;Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife, Spain |
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| Abstract: | We present the results of a deep optical–near-infrared (optical–NIR) multi-epoch survey covering 2.5 deg2 of the Pleiades open star cluster to search for new very low-mass brown dwarf members. A significant (～5 yr) epoch difference exists between the optical (CFH12k I -, Z -band) and NIR (UKIRT WFCAM J -band) observations. We construct I , I ? Z and Z , Z ? J colour–magnitude diagrams to select candidate cluster members. Proper motions are computed for all candidate members and compared to the background field objects to further refine the sample. We recover all known cluster members within the area of our survey. In addition, we have discovered nine new candidate brown dwarf cluster members. The seven faintest candidates have red Z ? J colours and show blue NIR colours. These are consistent with being L- and T-type Pleiads. Theoretical models predict their masses to be around 11 M Jup. |
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| Keywords: | stars: low-mass brown dwarfs open clusters and associations: individual: Pleiades |
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