Related papers: Tempawral: A Time-Resolved Retrieval Framework for…
Brown dwarfs provide a unique opportunity to study atmospheres and their physical and chemical processes with high precision, especially in temperature ranges relevant to exoplanets. In this study, we performed high-resolution ($R \sim…
Rotational modulations of emission spectra in brown dwarf and exoplanet atmospheres show that clouds are often distributed non-uniformly in these ultracool atmospheres. The spatial heterogeneity in cloud distribution demonstrates the impact…
Exoplanetary atmospheric retrieval refers to the inference of atmospheric properties of an exoplanet given an observed spectrum. The atmospheric properties include the chemical compositions, temperature profiles, clouds/hazes, and energy…
Previous studies showed that hydro-climate processes are stochastic and complex systems, and it is difficult to discover the hidden patterns in the all non-stationary data and thoroughly understand the hydro-climate relationships. For the…
Atmospheric retrievals of exoplanetary transmission spectra provide important constraints on various properties such as chemical abundances, cloud/haze properties, and characteristic temperatures, at the day-night atmospheric terminator. To…
SIMP-0136 is a T2.5 brown dwarf whose young age ($200\pm50$~Myr) and low mass ($15\pm3$~M$_{\rm Jup}$) make it an ideal analogue for the directly imaged exoplanet population. With a 2.4 hour period, it is known to be variable in both the…
Atmospheric retrievals of exoplanet transmission spectra allow constraints on the composition and structure of the day-night terminator region. Such retrievals in the past have typically assumed one-dimensional temperature structures which…
Brown dwarfs and planetary-mass companions display rotationally modulated photometric variability, especially those near the L/T transition. This variability is commonly attributed to top-of-atmosphere (TOA) inhomogeneities, with proposed…
Upcoming James Webb Space Telescope (JWST) observations will allow us to study exoplanet and brown dwarf atmospheres in great detail. The physical interpretation of these upcoming high signal-to-noise observations requires precise…
Numerous observational evidence has suggested the presence of active meteorology in the atmospheres of brown dwarfs. A near-infrared brightness variability has been observed. Clouds have a major role in shaping the thermal structure and…
Thermal emission spectra of exoplanets provide constraints on the chemical compositions, pressure-temperature (P-T) profiles, and energy transport in exoplanetary atmospheres. Accurate inferences of these properties rely on the robustness…
We developed a simple, physical and self-consistent cloud model for brown dwarfs and young giant exoplanets. We compared different parametrisations for the cloud particle size, by either fixing particle radii, or fixing the mixing…
Constraining L dwarf properties from their spectra is challenging. Near-infrared spectra probe a limited range of pressures, while many species condense within their photospheres. Condensation creates two complexities: gas-phase species…
The complexity of atmospheric retrieval models is largely data-driven and one-dimensional models have generally been considered adequate with current data quality. However, recent studies have suggested that using 1D models in retrievals…
We present a technique to identify spectrophotometrically variable L7-T3 brown dwarfs with single-epoch, low-resolution, near-infrared SpeX spectra. We calculated spectral indices on known variable brown dwarfs and used them to select 11…
The last few years has seen a dramatic increase in the number of exoplanets known and in the range of methods for characterising their atmospheric properties. At the same time, new discoveries of increasingly cooler brown dwarfs have pushed…
The high-contrast imaging technique is meant to provide insight into those planets orbiting several astronomical units from their host star. Space missions such as WFIRST, HabEx, and LUVOIR will measure reflected light spectra of cold…
We present an improved, hybrid CPU-GPU atmospheric retrieval code, Helios-r2, which is applicable to medium-resolution emission spectra of brown dwarfs, in preparation for precision atmospheric spectroscopy in the era of the James Webb…
The rotational spectral modulation (spectro-photometric variability) of brown dwarfs is usually interpreted as a sign of the presence of inhomogeneous cloud covers in the atmosphere. This paper aims at exploring the role of temperature…
Comparisons of atmospheric retrievals can reveal powerful insights on the strengths and limitations of our data and modeling tools. In this paper, we examine a sample of 5 similar effective temperature (Teff) or spectral type L dwarfs to…