Related papers: Atmospheric Waves Driving Variability and Cloud Mo…
A variety of observations provide evidence for vigorous motion in the atmospheres of brown dwarfs and directly imaged giant planets. Motivated by these observations, we examine the dynamical regime of the circulation in the atmospheres and…
Spatial heterogeneity and temporal variability are general features in planetary weather and climate, due to the effects of planetary rotation, uneven stellar flux distribution, fluid motion instability, etc. In this study, we investigate…
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…
We report on I band photometric observations of 21 stars with spectral types between M8 and L4 made using the Isaac Newton Telescope. The total amount of time for observations which had a cadence of <2.3 mins was 58.5 hrs, with additional…
Isolated planetary-mass objects share their mass range with planets but do not orbit a star. They lack the necessary mass to support fusion in their cores and thermally radiate their heat from formation as they cool, primarily at infrared…
Recent studies found that atmospheric superrotation (i.e., west-to-east winds over the equator) on tidally locked planets can modify the phase of planetary waves. But, a clear relationship between the superrotation and the magnitude of the…
As part of the Young Stellar Object VARiability (YSOVAR) program, we monitored NGC 1333 for ~35 days at 3.6 and 4.5 um using the Spitzer Space Telescope. We report here on the mid-infrared variability of the point sources in the…
We present a study of 323 photometrically variable young stellar objects that are likely members of the North America and Pelican (NAP) nebulae star forming region. To do so, we utilize over two years of data in the $g$ and $r$ photometric…
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…
Doppler Imaging produces 2D global maps of rotating objects using high-dispersion spectroscopy. When applied to brown dwarfs and extrasolar planets, this technique can constrain global atmospheric dynamics and/or magnetic effects on these…
Ground-based and spacecraft telescopic observations, combined with an intensive modeling effort, have greatly enhanced our understanding of hot giant planets and brown dwarfs over the past ten years. Although these objects are all fluid,…
We present two epochs of MPG/ESO 2.2m GROND simultaneous 6-band ($r'i'z'JHK$) photometric monitoring of the closest known L/T transition brown dwarf binary WISE J104915.57-531906.1AB. We report here the first resolved variability monitoring…
Models of brown dwarf atmospheres suggest they exhibit complex physical behaviour. Observations have shown that they are indeed dynamic, displaying small photometric variations over timescales of hours. Here I report results of infrared…
We report on a search for variability in the young brown dwarf SST1624 (~M7 spectral type, M~0.05Msol), previously found to feature an expanding gaseous shell and to undergo quasi-spherical mass loss. We find no variability on timescales of…
The temperature of a circumbinary disc edge should undulate due to variations in illumination as a function of binary orbital phase. We explore circumbinary disc temperature variations as a source of broad-band infrared light curve…
The inwards scattering of planetesimals towards white dwarfs is expected to be a stochastic process with variability on human time-scales. The planetesimals tidally disrupt at the Roche radius, producing dusty debris detectable as excess…
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 present the first detection of photometric variability of a spectroscopically-confirmed Y dwarf. The Infrared Array Camera on board the Spitzer Space Telescope was used to obtain times series photometry at 3.6 and 4.5 microns over a…
A variety of observational evidence demonstrates that brown dwarfs exhibit active atmospheric circulations. In this study we use a shallow-water model to investigate the global atmospheric dynamics in the stratified layer overlying the…
We perform a comprehensive analysis of the superorbital modulation in the ultracompact X-ray source 4U 1820-303, consisting of a white dwarf accreting onto a neutron star. Based on RXTE data, we measure the fractional amplitude of the…