Related papers: Self-Consistent Modeling of Metastable Helium Exop…
Stellar heating causes atmospheres of close-in exoplanets to expand and escape. These extended atmospheres are difficult to observe because their main spectral signature - neutral hydrogen at ultraviolet wavelengths - is strongly absorbed…
Observational evidence for escaping exoplanet atmospheres has been obtained for a few exoplanets to date. It comes from strong transit signals detected in the ultraviolet, most notably in the wings of the hydrogen Lyman-$\alpha$…
Atmospheric escape is considered to be one of the main channels for evolution in sub-Jovian planets, particularly in their early lives. While there are several hypotheses proposed to explain escape in exoplanets, testing them with…
The HeI 1083nm transit signature is commonly used in tracing escaping planetary atmospheres. However, it can be affected by stellar activity, complicating detections and interpretations of atmospheric escape. We model how stellar activity…
Planetary magnetic fields can affect the predicted mass loss rate for close-in planets that experience large amounts of UV irradiation. In this work, we present a method to detect the magnetic fields of close-in exoplanets undergoing…
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…
We use Keck/NIRSPEC to survey a sample of of young ($<$1 Gyr), short period mini Neptunes orbiting nearby K dwargs to measure their mass loss via the metastable helium line. We detect helium absorption from all four of the targets in our…
Probing the evaporation of exoplanet atmospheres is key to understanding the formation and evolution of exoplanetary systems. The main tracer of evaporation in the UV is the Lyman-alpha transition, which can reveal extended exospheres.…
The helium absorption triplet at a wavelength of 10,833 \AA\ has been proposed as a way to probe the escaping atmospheres of exoplanets. Recently this feature was detected for the first time using Hubble Space Telescope (HST) WFC3…
The absorption signals of metastable He in HD 209458b and several other exoplanets can be explained via escaping atmosphere model with a subsolar He/H ratio. The low abundance of helium can be a result of planet formation if there is a…
We report helium absorption from the escaping atmosphere of TOI 560.01 (HD 73583b), a $R=2.8 R_\oplus$, $P=6.4$ d mini Neptune orbiting a young ($\sim$600 Myr) K dwarf. Using Keck/NIRSPEC, we detect a signal with an average depth of $0.68…
Among highly irradiated exoplanets, some have been found to undergo significant hydrodynamic expansion traced by atmospheric escape. To better understand these processes in the context of planetary evolution, we propose NIGHT (the…
Exoplanets with substantial Hydrogen/Helium atmospheres have been discovered in abundance, many residing extremely close to their parent stars. The extreme irradiation levels these atmospheres experience causes them to undergo hydrodynamic…
Escaping exoplanet atmospheres have been observed as deep transit signatures in a few specific spectral lines. Detections have been made in the hydrogen Ly-$\alpha$ line, the metastable helium line at 10830 {\AA} and some UV lines of…
The metastable helium line at 1083 nm can be used to probe the extended upper atmospheres of close-in exoplanets and thus provide insight into their atmospheric mass loss, which is likely to be significant in sculpting their population. We…
Transmission spectroscopy of WASP-107b revealed 7-8% absorption at the position of metastable HeI triplet at 10830 {\AA} in Doppler velocity range of [-20; 10] km/s, which is stronger than that measured in other exoplanets. With a dedicated…
Infrared observations of metastable 2$^3$S helium absorption with ground- and space-based spectroscopy are rapidly maturing, as this species is a unique probe of exoplanet atmospheres. Specifically, the transit depth in the triplet feature…
This paper presents simulations of the metastable helium (He*) observations of WASP-107b, so far the highest signal-to-noise ratio detection that is confirmed by three different instruments. We employ full 3D hydrodynamics coupled with…
The He I line at 1.08 $\mu$m is a valuable tracer of atmospheric escape in exoplanet atmospheres. We expand past networks used to predict the absorbing He(2$^3S$) by including, firstly, processes that involve H$_2$ and some molecular ions…
Aeronomy, the study of Earth's upper atmosphere and its interaction with the local space environment, has long traced changes in the thermospheres of Earth and other solar system planets to solar variability in the X-ray and extreme…