Koen, ChrisIshihara, Akika2013-10-202013-10-202006Koen, C. & Ishihara, A. (200). Near-infrared time-series photometry of six fields in the young open cluster IC 2391. Monthly Notices of the Royal Astronomical Society, 369:846–8520035-8711http://hdl.handle.net/10566/775Fields containing targets of spectral types later than M5 were monitored in JHKs for about 7 h each. None of the targets showed variability at levels exceeding 0.02 (or smaller, in some cases). Seven new variable stars were discovered serendipitously. The large number of measurements (more than 50) of each field allows the construction of accurate colour–magnitude and colour– colour diagrams. These could be used to identify a small number of candidate very cool objects.en© 2006 copyright Oxford University Press. This file may be freely used for educational purposes, as long as it is not altered in any way. Acknowledgement of the authors and the source is required.Stars: low-mass, brown dwarfsStars: variables: otherArticle