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Title: X-ray emission from a brown dwarf in the Pleiades
Authors: Briggs, K. R.
Pye, J. P.
First Published: 11-Sep-2004
Publisher: Oxford University Press (OUP), Royal Astronomical Society
Citation: Monthly Notices of the Royal Astronomical Society, 2004, 353 (2), pp.673-680
Abstract: We report on the first detection of X-ray emission from a brown dwarf in the Pleiades, the M7-type Roque 14, obtained using the EPIC detectors on XMM–Newton. This is the first X-ray detection of a brown dwarf intermediate in age between ≈12 and ≈320 Myr. The emission appears persistent, although we cannot rule out flare-like behaviour with a decay time-scale >4 ks. The time-averaged X-ray luminosity of LX≈ 3.3 ± 0.8 × 1027 erg s−1 and its ratios with the bolometric (LX/Lbol≈ 10−3.05) and Hα (LX/LHα≈ 4.0) luminosities suggest magnetic activity similar to that of active main-sequence M dwarfs, such as the M7 old-disc star VB 8, although the suspected binary nature of Roque 14 merits further attention. No emission is detected from four proposed later-type Pleiades brown dwarfs, with upper limits to LX in the range 2.1–3.8 × 1027 erg s−1 and to log (LX/Lbol) in the range −3.10 to −2.91.
DOI Link: 10.1111/j.1365-2966.2004.08100.x
ISSN: 0035-8711
Type: Article
Rights: Archived with reference to SHERPA/RoMEO and publisher website. This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2004 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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