Related papers: Silicate Precursor Silane detected in Cold Low-Met…
We report the discovery of two companion sources to a strongly lensed galaxy SPT0418-47 ("ring") at redshift 4.225, targeted by the JWST Early Release Science program. We confirm that these sources are at a similar redshift as the ring…
Infrared excesses due to dusty disks have been observed orbiting white dwarfs with effective temperatures between 7200 K and 25000 K, suggesting that the rate of tidal disruption of minor bodies massive enough to create a coherent disk…
The precipitation of cloud particles in brown dwarf and exoplanet atmospheres establishes an ongoing downward flux of condensable elements. To understand the efficiency of cloud formation, it is therefore crucial to quantify the…
The atmospheric pressure-temperature profiles for transiting giant planets cross a range of chemical transitions. Here we show that the particular shape of these irradiated profiles for warm giant planets below 1300 K lead to striking…
The James Webb Space Telescope (JWST) offers exceptional spectral resolution and wavelength coverage, which are essential for studying the coldest brown dwarfs, particularly Y dwarfs. These objects are at the cold end of the sub-stellar…
We report on the characterization of a nearby (d = 11.2 pc) ultracool L dwarf (WISE J192512.78+070038.8; hereafter W1925) identified as a faint (G = 20.0) high proper motion (0.22"/yr) object in the Gaia Data Releases 1 and 2. A…
We present results from conducting a theoretical chemical analysis of a sample of benchmark companion brown dwarfs whose primary star is of type F, G or K. We summarize the entire known sample of these types of companion systems, termed…
We present the first emission spectrum of the hot Jupiter WASP-17 b using one eclipse observation from the JWST Near Infrared Imager and Slitless Spectrograph (NIRISS) Single Object Slitless Spectroscopy (SOSS) mode. Covering a wavelength…
The physical state and properties of silicates at conditions encountered in the cores of gas giants, ice giants and of Earth like exoplanets now discovered with masses up to several times the mass of the Earth remains mostly unknown. Here,…
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$300 K thermal inversion…
We address disequilibrum abundances of some simple molecules in the atmospheres of solar composition brown dwarfs and self-luminous extrasolar giant planets using a kinetics-based 1D atmospheric chemistry model. Our approach is to use the…
We present a distant T$-$type brown dwarf candidate at $\approx2.55$ kpc discovered in the Cosmic Evolution Early Release Science (CEERS) fields by James Webb Space Telescope (JWST) NIRCam. In addition to the superb sensitivity, we utilised…
We present the discovery of a companion to the Y-dwarf, CWISEP J193518.59-154620.3, the second Y-Y dwarf binary detected to date. Y-dwarfs are the coldest known free-floating objects ($<$ 500 K) and on average represent the lowest mass…
We present the first full JWST NIRSpec Prism and MIRI LRS 0.6 - 14 $\mu$m (R ~ 100) spectra and analysis of five ~ 133 Myr L dwarf members of the AB Doradus moving group and one probable $\sim 500$ Myr T dwarf of the Oceanus moving group…
We present HST STIS optical transmission spectroscopy of the cool Saturn-mass exoplanet WASP-39b from 0.29-1.025 micron, along with complementary transit observations from Spitzer IRAC at 3.6 and 4.5 micron. The low density and large…
Some sub-Neptune planets may host habitable conditions; for example "Hycean" worlds with H2 envelopes over liquid water oceans can maintain potentially hospitable pressures and temperatures at their surface. Recent JWST observations of…
A search for young substellar objects in the rho Oph cloud core region has been made using the deep-integration Combined Calibration Scan images of the 2MASS extended mission in J, H and Ks bands, and Spitzer IRAC images at 3.6, 4.5, 5.8…
Low mass (sub)stellar objects represent the low end of the initial mass function, the transition to free-floating planets and a prominent interloper population in the search for high-redshift galaxies. Without proper motions or…
The day and nightside temperatures of hot Jupiters are diagnostic of heat transport processes in their atmospheres. Recent observations have shown that the nightsides of hot Jupiters are a nearly constant 1100 K for a wide range of…
Young exoplanets provide a critical link between understanding planet formation and atmospheric evolution. Direct imaging spectroscopy allows us to infer the properties of young, wide orbit, giant planets with high signal-to-noise. This…