Related papers: Periodic photometric variability of the brown dwar…
We report the results of observations designed to investigate the spectroscopic signatures of dust clouds on the L2 brown dwarf Kelu-1. Time resolved medium resolution spectra show no significant evidence of variability in the dust…
We have resolved Kelu-1 into a binary system with a separation of ~290 mas using the Laser Guide Star Adaptive Optics system on the Keck II telescope. We have also re-analyzed a 1998 HST observation of Kelu-1 and find that the observed PSF…
We report the discovery of a photometric variability in the bright T2.5 brown dwarf SIMP J013656.5+093347. Continuous J-band photometry has been obtained for several hours on four different nights. The light curves show a periodic…
We have monitored the photometric variability of nine field L and T brown dwarfs for 10 nights during the course of one month with the Palomar 60 inch Telescope Near-Infrared Camera. Results of statistical analyses indicate that at least…
We have carried out multi-epoch, time-series differential I-band photometry of a large sample of objects in the south-east region of the young (~3 Myr), nearby (~350 pc) sigma Orionis open cluster. A field of ~1000 arcmin^2 was monitored…
A fraction of very low mass stars and brown dwarfs are known to be radio active, in some cases producing periodic pulses. Extensive studies of two such objects have also revealed optical periodic variability and the nature of this…
We present photometric light curves for a sample of 21 ultra cool M and L dwarfs in the field and in the young open clusters sigma Orionis and the Pleiades. Evidence for variability with RMS amplitudes (in the I band) of 0.01 to 0.055…
(Abridged) We present near-IR imaging of the nearby L dwarf Kelu-1 obtained with the Keck sodium laser guide star adaptive optics (LGS AO) system as part of a high angular resolution survey for substellar binaries. Kelu-1 was one of the…
We have monitored the benchmark L dwarf binary Kelu-1AB over the past 3 years to derive improved spectral types and luminosities for the individual components. The astrometric measurements enable us to compute the orbital parameters and…
We report CCD photometric monitoring of the nonemission ultracool dwarf BRI 0021-0214 (M9.5) obtained during 10 nights in 1995 November and 4 nights in 1996 August, with CCD cameras at 1 m class telescopes on the observatories of the Canary…
We used the optical and near-infrared imagers located on the Liverpool, the IAC80, and the William Herschel telescopes to monitor 18 M7$-$L9.5 dwarfs with the objective of measuring their rotation periods. We achieved accuracies typically…
Photometric I band light curves of 21 ultra cool M and L dwarfs are presented. Variability with amplitudes of 0.01 to 0.055 magnitudes (RMS) with typical timescales of an hour to several hours are discovered in half of these objects.…
We use 1-m class telescopes and the Transiting Exoplanet Survey Satellite (TESS) to explore the photometric variability of all known rapidly rotating ($v\sin{i}\gtrsim30$ km\,s$^{-1}$) ultra-cool ($\geq$M7) dwarfs brighter than…
We present simultaneous, multiband monitoring of 19 field M dwarfs (spectral types M2-M9). Significant variability was found in seven objects in at least one out of the three channels I, R and G. Two objects, LHS370 (M5V) and 2M1707+64…
We report $I$-band photometric observations of the radio-detected M9.5 dwarf BRI 0021-0214, obtained with the Galway Ultra Fast Imager (GUFI) on the 1.8m Vatican Advanced Technology Telescope VATT at Mt. Graham International Observatory,…
We report on the results of an I-band photometric variability survey of eighteen L dwarfs. We find that seven exhibit statistically significant variations above the 95.4% confidence level with root-mean-square scatter (including photometric…
We present multi-colour photometry of four field ultracool dwarfs with the triple-beam photometer ultracam. Data were obtained simultaneously in the Sloan-g' band and a specially designed narrow-band NaI filter. The previously reported…
Over the past few years monitoring programs have shown ultra cool dwarfs (UCDs) to be photometrically variable. Of the 60 sources monitored in the field and some 120 monitored in clusters, about 40% show variability in both cases. For mid…
We make use of the high photometric precision of Kepler to search for periodic modulations among 14 normal (DA- and DB-type, likely non-magnetic) hot white dwarfs (WDs). In five, and possibly up to seven of the WDs, we detect periodic, ~2…
We provide an overview of stellar variability in the first quarter of data from the Kepler mission. The intent of this paper is to examine the entire sample of over 150,000 target stars for periodic behavior in their lightcurves, and relate…