Open AccessPeriodic photometric variability of the brown dwarf Kelu‐1
Author(s) -
Clarke F. J.,
Tinney C. G.,
Covey K. R.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05308.x
Subject(s) - physics , light curve , rotation period , astrophysics , brown dwarf , radius , amplitude , astronomy , rotation (mathematics) , line of sight , galaxy rotation curve , photometry (optics) , variation (astronomy) , stars , optics , geometry , galaxy , galaxy formation and evolution , computer security , mathematics , computer science
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.