IngentaConnect Periodic photometric variability of the brown dwarf Kelu-1

Authors: Clarke, F. J.¹; Tinney, C. G.²; Covey, K. R.³

Source: Monthly Notices of the Royal Astronomical Society, Volume 332, Number 2, May 2002 , pp. 361-366(6)

Abstract:

We have detected a strong periodicity of 1.80±0.05 h in photometric observations of the brown dwarf Kelu-1. The peak-to-peak amplitude of the variation is ∼1.1 per cent (11.9±0.8 mmag) in a 41-nm wide filter centred on 857 nm and including the dust/temperature-sensitive TiO and CrH bands. We have identified two plausible causes of variability: surface features rotating in to and out of view and so modulating the light curve at the rotation period; or ellipsoidal variability caused by an orbiting companion. In the first scenario, we combine the observed v sin i of Kelu-1 and standard model radius to determine that the axis of rotation is inclined at 65°±12° to the line of sight.

Keywords: techniques: photometric; stars: atmospheres; binaries: close; stars: low-mass, brown dwarfs; stars: oscillations; stars: rotation

Document Type: Research article

DOI: 10.1046/j.1365-8711.2002.05308.x

Affiliations: 1: 1Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, 2: 2Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia and 3: 3 Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA

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