Related papers: Modelling helium in exoplanet atmospheres. A revis…
Transit observations of HD209458b in the UV revealed signatures of neutral magnesium escaping the planet's upper atmosphere. The absorption detected in the MgI line provides unprecedented information on the physical conditions at the…
Atmospheric escape of planets on short orbital periods, driven by the host star's irradiation, influences their evolution, composition, and atmospheric dynamics. Our main avenue to probe atmospheric escape is through the near-infrared…
Hydrostatic equilibrium is an excellent approximation for the dense layers of planetary atmospheres where it has been canonically used to interpret transmission spectra of exoplanets. Here we exploit the ability of high-resolution…
We aimed to build a new and updated C0-C2 chemical network to study the CHON disequilibrium chemistry of warm and hot exoplanet atmospheres that relies on extensively validated and recent state-of-the-art combustion networks. The…
The increasing number of detailed exoplanet observations offers an opportunity to refine our analyses and interpretations. Here, we show that atmospheres that appear volatile-rich and/or cloudy may instead be helium-rich. As transmission…
Interstellar neutral gas atoms penetrate the heliopause and reach 1~au, where they are detected by IBEX. The flow of neutral interstellar helium through the perturbed interstellar plasma in the outer heliosheath (OHS) results in creation of…
We simulate atmospheric fractionation in escaping planetary atmospheres using IsoFATE, a new open-source numerical model. We expand the parameter space studied previously to planets with tenuous atmospheres that exhibit the greatest helium…
An observing campaign (SOHO JOP 139), coordinated between ground based and SOHO instruments, has been planned to obtain simultaneous spectroheliograms of the same active region in several spectral lines. The chromospheric lines CaII K,…
Transit observations in the helium triplet around 10830 Angstrom are a successful tool to study exoplanetary atmospheres and their mass loss. Forming those lines requires ionisation and recombination of helium in the exoplanetary…
Neptune-size exoplanets are less studied as characterizing their atmospheres presents challenges due to their relatively small radius and atmospheric scale height. As the most common outcome of planet formation, these planets are crucial…
Below $\sim 630$~mK, the \4he atom mass flux, $F$, that passes through a cell filled with solid hcp \4he in the pressure range 25.6 - 26.4~bar, rises with falling temperature and at a temperature $T_d$ the flux drops sharply. The flux above…
Quantitative analyses of extreme helium stars to date face the difficulty that theory fails to reproduce the observed helium lines in their entirety, wings and line cores. Here, we demonstrate how the issues can be resolved using…
Hydrogen recombination is one of the most important atomic processes in many astrophysical objects such as Type II supernova (SN~II) atmospheres, the high redshift universe during the cosmological recombination era, and H II regions in the…
Short-period sub-Neptunes are common in extrasolar systems. These sub-Neptunes are generally thought to have primary atmospheres of protoplanetary-disk gas origin. However, atmospheric escape followed by degassing from their interiors can…
Interpretations of exoplanetary transmission spectra have been undermined by apparent obscuration due to clouds/hazes. Debate rages on whether weak H$_2$O features seen in exoplanet spectra are due to clouds or inherently depleted oxygen.…
Observations of cooler atmospheres of super-Earths and Neptune sized objects often show flat transmission spectra. The most likely cause of this trend is the presence of aerosols (i.e. clouds and hazes) in the atmospheres of such objects.…
GJ 436b is the first extrasolar planet discovered that resembles Neptune in mass and radius. The particularly interesting property of Neptune-sized planets is that their mass Mp and radius Rp are close to theoretical M-R relations of water…
Producing optimized and accurate transmission spectra of exoplanets from telescope data has traditionally been a manual and labor-intensive procedure. Here we present the results of the first attempt to improve and standardize this…
The hot Jupiter WASP-80b has been identified as a possible excellent target for detecting and measuring HeI absorption in the upper atmosphere. We observed 4 primary transits of WASP-80b in the optical and near-IR using the HARPS-N and…
Jupiter's atmosphere has been observed to be depleted in helium (Yatm~0.24), suggesting active helium sedimentation in the interior. This is accounted for in standard Jupiter structure and evolution models through the assumption of an…