Related papers: Correlated spectral variability in brown dwarfs
We have used an innovative tuneable filter technique to carry out a search for the variability signatures of meterological processes in the atmospheres of two nearby brown dwarfs. We find no evidence for variability in the L-type brown…
We present evolutionary calculations for very-low-mass stars and brown dwarfs based on synthetic spectra and non-grey atmosphere models which include dust formation and opacity, i.e. objects with $\te\simle 2800$ K. The interior of the most…
We have monitored photometrically the Y0 brown dwarf WISEP J173835.52+273258.9 (W1738) at both near- and mid-infrared wavelengths. This ~1 Gyr-old 400K dwarf is at a distance of 8pc and has a mass around 5 M_Jupiter. We observed W1738 using…
Time-resolved observations of brown dwarfs' rotational modulations provide powerful insights into the properties of condensate clouds in ultra-cool atmospheres. Multi-wavelength light curves reveal cloud vertical structures, condensate…
Rotationally-modulated variability of brown dwarfs and giant planets provides unique information about their surface brightness inhomogeneities, atmospheric circulation, cloud evolution, vertical atmospheric structure, and rotational…
We use the Wide Field Camera 3 on the {\sl Hubble Space Telescope} to spectrophotometrically monitor the young L7.5 companion HD~203030B. Our time series reveal photometric variability at 1.27\,$\mu$m and 1.39\,$\mu$m on time scales…
We investigate the sensitivity to temperature and gravity of the strong absorption features in the J- and K-band spectra of substellar objects. We compare the spectra of giants and young M dwarfs (of low gravity) to field M and L dwarfs (of…
We present the discovery of 49 new photometrically classified T dwarfs from the combination of large infrared and optical surveys combined with follow-up TNG photometry. We used multi-band infrared and optical photometry from the UKIRT and…
Condensate clouds fundamentally impact the atmospheric structure and spectra of exoplanets and brown dwarfs but the connections between surface gravity, cloud structure, dust in the upper atmosphere, and the red colors of some brown dwarfs…
We report the results of optical monitoring for a sample of 11 blazars including 10 BL Lacs and 1 Flat Spectrum Radio Quasar (FSRQ). We have measured the multiband optical flux and colour variations in these blazars on intra-day and…
We present $I$-band time-series photometric variability studies of three known nearby ($\sim$ 140 pc) and young ( $\sim$ 1 Myr) brown dwarfs (BD) in the Taurus star-forming region in the Perseus Molecular Cloud. From 10 nights of…
Recent JWST/NIRSpec observations have revealed strong methane emission at 3.326 microns in the $\approx$482 K brown dwarf CWISEP J193518.59$-$154620.3 (W1935). Atmospheric modeling suggests the presence of a $\approx$300 K thermal inversion…
Significant populations of field L and T dwarfs are now known, and we anticipate the discovery of even cooler dwarfs by Spitzer and ground-based infrared surveys. However, as the number of known L and T dwarfs increases so does the range in…
We report the detection of H{$\alpha$} emission in the T dwarf (methane brown dwarf) 2MASSW J1237392+652615 over three days using the Keck Low Resolution Imaging Spectrograph. The measured line flux, log(L$_{H{\alpha}}$/L$_{bol}$) = $-$4.3,…
We present a large forward-modeling analysis for 55 late-T (T7-T9) dwarfs, using low-resolution ($R\approx150$) near-infrared spectra and cloudless Sonora-Bobcat model atmospheres. We derive the objects' effective temperatures, surface…
Recent observation of linear optical polarization from brown dwarfs confirms the dust hypothesis in the atmospheres of brown dwarfs with effective temperature higher than 1400 K. The observed polarization could arise due to dust scattering…
With the improvements in radio interferometry sensitivity, the quest for coherent radio emission from exoplanets and ultra-cool dwarfs, which is indicative of their magnetic fields, has gained significant momentum in recent years. We…
Evidence of disequilibrium chemistry due to vertical mixing in the atmospheres of many T and Y-dwarfs has been inferred due to enhanced mixing ratios of CO and reduced NH$_3$. Atmospheric models of planets and brown dwarfs typically…
WD0137-349 is a white dwarf-brown dwarf binary system in a 116 minute orbit. We present radial velocity observations and multiwaveband photometry from V, R and I in the optical, to J, H and Ks in the near-IR and [3.6], [4.5], [5.8] and…
We have found a dramatic change in the spectra of late-type M dwarfs at wavelengths shorter than 0.75 microns. Comparisons with synthetic spectra illustrate that this change is well explained by the presence of dust. It thus seems that a…