相关论文: Self-Consistent Modeling of Metastable Helium Exop…
The best-characterized exoplanets to date are planets on close-in transiting orbits around their host stars. The high level of irradiation and transiting geometry of these objects make them ideal targets for atmospheric investigations.…
The transmission spectra of exoplanet atmospheres observed with the Hubble Space Telescope (HST) in the near-infrared range (1.1-1.65$\mu$m) frequently show evidence for some combination of clouds and hazes. Identification of systematic…
The high energy radiation environment around M dwarf stars strongly impacts the characteristics of close-in exoplanet atmospheres, but these wavelengths are difficult to observe due to geocoronal and interstellar contamination. On account…
A critically important process affecting the climate evolution and potential habitability of an exoplanet is atmospheric escape, in which high-energy radiation from a star drives the escape of hydrogen atoms and other light elements from a…
We present Hubble Space Telescope optical and near-ultraviolet transmission spectra of the transiting hot-Jupiter HD189733b, taken with the repaired Space Telescope Imaging Spectrograph (STIS) instrument. The resulting spectra cover the…
Large-scale exoplanet search surveys have shown evidence that atmospheric escape is a ubiquitous process that shapes the evolution and demographics of planets. However, we lack a detailed understanding of this process because very few…
A notable fraction of helium observations probing the evaporating atmospheres of short-period gas giants at 1083~nm exhibit a blueshift during transit, which might be indicative of a day-to-night side flow. In this study, we explore the gas…
Motivated by the recent surge in interest concerning white dwarf (WD) planets, this work presents the first numerical exploration of WD-driven atmospheric escape, whereby the high-energy radiation from a hot/young WD can trigger the outflow…
We present the detection of helium in the extended atmosphere of the sub-Saturn WASP-107b using high resolution ($R \approx 25000$) near-infrared spectra from Keck II/NIRSPEC. We find peak excess absorption of $7.26 \pm 0.24\%$ (30$\sigma$)…
The technique of transmission spectroscopy allows us to constrain the chemical composition of the atmospheres of transiting exoplanets. It relies on very high signal-to-noise spectroscopic (or spectrophotometric) observations and is thus…
Atomic hydrogen escaping from the planet HD209458b provides the largest observational signature ever detected for an extrasolar planet atmosphere. However, the Space Telescope Imaging Spectrograph (STIS) used in previous observational…
An important evolutionary pathway for planetary atmospheres is escape to space, which has been studied on Earth and Mars for several decades and more recently in exoplanets. A particularly important regime is the hydrodynamic escape,…
We present a new detailed model of the He I collisional-recombination spectrum based on the most up-to-date atomic data. The model accounts for radiative transfer effects and the influence of a non-zero optical depth in He I lines arising…
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…
Absorption of stellar H\alpha\ by the upper atmosphere of the planet HD189733b has recently been detected by Jensen et al. Motivated by this observation, we have developed a model for atomic hydrogen in the n=2 state and compared the…
We report on a spectroscopic determination of the atmospheric parameters and chemical abundance of the parent star of the recently discovered transiting planet {TrES-2}. A detailed LTE analysis of a set of \ion{Fe}{1} and \ion{Fe}{2} lines…
Transit spectroscopy of terrestrial planets around nearby M dwarfs is a primary goal of space missions in coming decades. 3-D climate modeling has shown that slow-synchronous rotating terrestrial planets may develop thick clouds at the…
H$_2$O is a key molecule in characterizing atmospheres of temperate terrestrial planets, and observations of transmission spectra are expected to play a primary role in detecting its signatures in the near future. The detectability of…
One of the most well-studied exoplanets to date, HD 189733 b, stands out as an archetypal hot Jupiter with many observations and theoretical models aimed at characterizing its atmosphere, interior, host star, and environment. We report here…
M-type stars are prime targets for exoplanet searches within their habitable zones (HZs). These stars also exhibit significant magnetic flaring activity, particularly during their first billion years, which can potentially accelerate the…