JHK
s time-series observations of a few ultracool dwarfs |
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| Authors: | C Koen T Tanabé M Tamura N Kusakabe |
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| Institution: | Department of Statistics, University of the Western Cape, Private Bag X17, Bellville 7535, Cape, South Africa;South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape, South Africa;Institute of Astronomy, School of Science, The University of Tokyo, Mitaka, Tokyo 181-0015, Japan;National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan;Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan |
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| Abstract: | The M8.5 object SSSPM J0109−5101 has recently been shown to be both a periodic and a flaring variable, based on optical observations in the extreme red. More than 16 h of monitoring in the near-infrared (NIR) reported here failed to show any variability. Similarly, no NIR variability could be detected in intensive monitoring of three other suspected optical variables. This paper also reports on photometry of half a dozen targets monitored over a few weeks, and on the comparison of intensive monitoring at different epochs. In only one case, that of the T dwarf binary ε Indi Bab, is there good evidence for variability. Our results allow stringent limits to be placed on the NIR variability levels in a large sample of ultracool dwarfs. |
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| Keywords: | techniques: photometric stars: individual: ε Indi Bab stars: individual: SSSPM J0109−5101 stars: low-mass brown dwarfs stars: variables: other |
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