IC and RC band time-series observations of some bright ultracool dwarfs


  • Chris Koen

    Corresponding author
    1. Department of Statistics, University of the Western Cape, Private Bag X17, Bellville, 7535 Cape, South Africa
    2. South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape, South Africa
      E-mail: ckoen@uwc.ac.za
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E-mail: ckoen@uwc.ac.za


The results of more than 100 h of CCD photometric monitoring of 10 L dwarfs and two T dwarfs are presented. Reasonable evidence is shown for IC band variability in DENIS 0255−4700, DENIS 1705−0516 and 2M 2104−1037. Substantial brightening of the T dwarf binary ε Indi Bab was observed over the course of 3.6 h; it is unlikely that this could have been caused by surface spots. No unequivocal variability could be detected in the RC band.