Related papers: HELIOS-Retrieval: An Open-source, Nested Sampling …
Clouds are ubiquitous in exoplanet atmospheres and represent a challenge for the model interpretation of their spectra. Complex cloud models are too numerically costly for generating a large number of spectra, while more efficient models…
We present the open-source radiative transfer code named HELIOS, which is constructed for studying exoplanetary atmospheres. In its initial version, the model atmospheres of HELIOS are one-dimensional and plane-parallel, and the equation of…
Directly-imaged exoplanets are unexplored laboratories for the application of the spectral and temperature retrieval method, where the chemistry and composition of their atmospheres are inferred from inverse modeling of the available data.…
The formation and evolution pathway for the directly-imaged multi-planetary system HR 8799 remains mysterious. Accurate constraints on the chemical composition of the planetary atmosphere(s) are key to solving the mystery. We perform a…
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…
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…
Hi-resolution spectroscopy (R > 25,000) has recently emerged as one of the leading methods to detect atomic and molecular species in the atmospheres of exoplanets. However, it has so far been lacking in a robust method to extract…
We present new methodological features and physical ingredients included in the 1D radiative transfer code HELIOS, improving the hemispheric two-stream formalism. We conduct a thorough intercomparison survey with several established forward…
Comparing chemical abundances of a planet and the host star reveals the origin and formation path. Stellar abundance is measured with high-resolution spectroscopy. Planet abundance, on the other hand, is usually inferred from low-resolution…
We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. We run millions of 1D atmosphere models in order to cover the large range of allowed parameter space,…
High-resolution Doppler spectroscopy has been used to detect several chemical species in exoplanetary atmospheres. Such detections have traditionally relied on cross correlation of observed spectra against spectral model templates, an…
Secondary eclipse spectroscopy provides invaluable insights into the temperatures and compositions of exoplanetary atmospheres. We carry out a systematic temperature and abundance retrieval analysis of nine exoplanets (HD189733b, HD209458b,…
Current observations of the atmospheres of close-in exoplanets are predominantly obtained with two techniques: low-resolution spectroscopy with space telescopes and high-resolution spectroscopy from the ground. Although the observables…
Aims: ARCiS, a novel code for the analysis of exoplanet transmission and emission spectra is presented. The aim of the modelling framework is to provide a tool able to link observations to physical models of exoplanet atmospheres. Methods:…
The four directly imaged planets orbiting the star HR 8799 are an ideal laboratory to probe atmospheric physics and formation models. We present more than a decade's worth of Keck/OSIRIS observations of these planets, which represent the…
With four companions at separations from 16 to 71 au, HR 8799 is a unique target for direct imaging, presenting an opportunity for the comparative study of exoplanets with a shared formation history. Combining new VLTI/GRAVITY observations…
The retrieval approach is currently a standard method for deriving atmospheric properties from observed spectra of exoplanets. However, the approach ignores disequilibrium chemistry in most current retrieval codes, which can lead to…
Aims. To create a retrieval framework which encapsulates the 3D nature of exoplanet atmospheres, and to apply it to observed emission phase curve and transmission spectra of hot Jupiter exoplanet WASP-43b. Methods. We present our 3D…
Recent spectroscopic observations of transiting hot Jupiters have permitted the derivation of the thermal structure and molecular abundances of H2O, CO2, CO, and CH4 in these extreme atmospheres. Here, for the first time, we apply the…
Using the Keck Planet Imager and Characterizer (KPIC), we obtained high-resolution (R$\sim$35,000) $K$-band spectra of the four planets orbiting HR 8799. We clearly detected \water{} and CO in the atmospheres of HR 8799 c, d, and e, and…