相关论文: 3D model of hydrogen atmospheric escape from HD209…
We report on a search for H-alpha absorption in four exoplanets. Strong features at H-alpha are observed in the transmission spectra of both HD 189733b and HD 209458b. We attempt to characterize and remove the effects of stellar variability…
Since the mass loss rates are the function of the mean density of the planet and the stellar irradiation, we calculated about 450 models covering planets with different densities and stellar irradiation. Our results show that the mass loss…
Recent observations of planetary atmospheres in HAT-P-32 b and HAT-P-67 b reveal extensive outflows reaching up to hundreds of planetary radii. The helium 1083 nm light curves for these planets, captured across their full orbits, show…
Water, methane and carbon-monoxide are expected to be among the most abundant molecules besides molecular hydrogen in the hot atmosphere of close-in EGPs. Transit observations in the mid-IR allow the atmospheric content of transiting…
Characterising the atmospheres of exoplanets is key to understanding their nature and provides hints about their formation and evolution. High-resolution measurements of the helium triplet, He(2$^{3}$S), absorption of highly irradiated…
K2-18 b is a transiting mini-Neptune that orbits a nearby (38 pc) cool M3 dwarf and is located inside its region of temperate irradiation. We report on the search for hydrogen escape from the atmosphere K2-18 b using Lyman-$\alpha$ transit…
Bathed in intense ionizing radiation, close-in gaseous planets undergo hydrodynamic atmospheric escape, which ejects the upper extent of their atmospheres into the interplanetary medium. Ultraviolet detections of escaping gas around…
We present a detailed three-dimensional radiative-hydrodynamical simulation of the well known irradiated exoplanet HD189733b. Our model solves the fully compressible Navier-Stokes equations coupled to wavelength-dependent radiative transfer…
The recent discovery of ``ultra-hot'' ($P < 1$ day) Neptunes has come as a surprise: some of these planets have managed to retain gaseous envelopes despite being close enough to their host stars to trigger strong photoevaporation and/or…
HIP94235 b, a 120 Myr old sub-Neptune, provides us the unique opportunity to study mass loss at a pivotal stage of the system's evolution: the end of a 100 million year (Myr) old phase of intense XUV irradiation. We present two observations…
Here, we study the dichotomy of the escaping atmosphere of the newly discovered close-in exoplanet AU Mic b. On one hand, the high EUV stellar flux is expected to cause a strong atmospheric escape in AU Mic b. On the other hand, the wind of…
We study the interactions between stellar wind and the extended hydrogen-dominated upper atmospheres of planets and the resulting escape of planetary pick-up ions from the 5 "super-Earths" in the compact Kepler-11 system and compare the…
The role of radiation pressure in shaping exoplanet photoevaporation remains a topic of contention. Radiation pressure from the exoplanet's host star has been proposed as a mechanism to drive the escaping atmosphere into a "cometary" tail…
This paper presents a detailed hydrostatic model of the upper atmosphere of HD 189733b, with the goal of constraining its temperature, particle densities, and radiation field over the pressure range $10^{-4}-10\, \mu \rm bar$, where the…
A complete reassessment of the HST observations of the transits of the extrasolar planet HD209458b has provided a transmission spectrum of the atmosphere over a wide range of wavelengths. Analysis of the NaI absorption line profile has…
Using the new Cosmic Origins Spectrograph (COS) on the {\it Hubble Space Telescope (HST)}, we obtained moderate-resolution, high signal/noise ultraviolet spectra of HD 209458 and its exoplanet HD 209458b during transit, both orbital…
Hot Jupiters might reside inside the Alfv\'en surface of their host star wind, where the stellar wind is dominated by magnetic energy. The implications of such a sub-Alfv\'enic environment for atmospheric escape are not fully understood.…
Atmospheric escape of close-in exoplanets can be driven by high energy radiation from the host star. The planetary outflows interacting with the stellar wind may generate observable transit signals that depend on the strength of the stellar…
HAT-P-32 b is the first exoplanet for which absorption in hydrogen and helium lines has been measured simultaneously. In addition to the relatively large maximum depth of ~5% in both lines, observations have revealed very long pre-transit…
Here we describe the observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of the "Hot-Jupiters". In particular, observations and theoretical modeling of Hot-Jupiter evaporation are described. The…