Related papers: How to Distinguish between Cloudy Mini-Neptunes an…
Some super Earths and mini Neptunes will likely have thick atmospheres that are not H2-dominated. We have developed a photochemistry-thermochemistry kinetic-transport model for exploring the compositions of thick atmospheres on super Earths…
Temperate sub-Neptunes are compelling targets for detecting liquid-water oceans beyond the Solar System. If water-rich and lacking massive hydrogen-helium envelopes, these planets could sustain liquid layers beneath their atmospheres…
Recent surveys have revealed that planets intermediate in size between Earth and Neptune ("super-Earths") are among the most common planets in the Galaxy. Atmospheric studies are the next step toward developing a comprehensive understanding…
Recent work on the characterization of small exoplanets has allowed us to accumulate growing evidence that the sub-Neptunes with radii greater than $\sim2.5\,R_\oplus$ often host H$_2$/He-dominated atmospheres both from measurements of…
The recent discovery and initial characterization of sub-Neptune-sized exoplanets that receive stellar irradiance of approximately Earth's raised the prospect of finding habitable planets in the coming decade, because some of these…
The demographics of sub-Jovian planets around low-mass stars is dominated by populations of ``sub-Neptunes" and ``super-Earths", distinguished by the presence or absence of envelopes of low-molecular weight volatiles, i.e., H2, He, and H2O.…
GJ1214b is thought to be either a mini-Neptune with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. In the case of a hydrogen-rich atmosphere, molecular absorption and scattering processes may result in…
Mildly irradiated mini-Neptunes have densities potentially consistent with them hosting substantial liquid water oceans (`Hycean' planets). The presence of CO2 and simultaneous absence of ammonia (NH3) in their atmospheres has been proposed…
Astronomers are debating whether the plentiful "sub-Neptune" exoplanets -- worlds a bit larger than Earth but smaller than Neptune -- are predominantly rocky planets, water-rich "ocean worlds," or gas-enshrouded mini-Neptunes. This question…
With no analogues in the Solar System, the discovery of thousands of exoplanets with masses and radii intermediate between Earth and Neptune was one of the big surprises of exoplanet science. These super-Earths and sub-Neptunes likely…
The study of temperate sub-Neptunes is the new frontier in exoplanetary science. A major development in the past year has been the first detection of carbon-bearing molecules in the atmosphere of a temperate sub-Neptune, K2-18 b, a possible…
We present a search for helium in the upper atmospheres of three sub-Neptune size planets to investigate the origins of these ubiquitous objects. The detection of helium for a low density planet would be strong evidence for the presence of…
Results from the Kepler mission indicate that the occurrence rate of small planets ($<3$ $R_\oplus$) in the habitable zone of nearby low-mass stars may be as high as 80%. Despite this abundance, probing the conditions and atmospheric…
Sub-Neptune planets, with sizes and masses between those of Earth and Neptune, dominate the exoplanet population. Sub-Neptunes are expected to be the most diverse family of the exoplanet population, potentially including rocky gas dwarfs,…
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…
Temperate exoplanets between the sizes of Earth and Neptune, known as "sub-Neptunes", have emerged as intriguing targets for astrobiology. It is unknown whether these planets resemble Earth-like terrestrial worlds with a habitable surface,…
Understanding the surface temperature and interior structure of cold-to-temperate sub-Neptunes is critical for assessing their habitability, yet direct observations are challenging. In this study, we investigate the impact of water…
Understanding the planetary envelope composition of sub-Neptune-type exoplanets is challenging due to the inherent degeneracy in their interior composition scenarios. Particularly, the planetary envelope's H2O/H2 ratio, which can also be…
Super-Earths span a wide range of bulk densities, indicating a diversity in interior conditions beyond that seen in the solar system. In particular, an emerging population of low-density super-Earths may be explained by volatile-rich…
We present three-dimensional atmospheric circulation models of GJ 1214b, a 2.7 Earth-radius, 6.5 Earth-mass super Earth detected by the MEarth survey. Here we explore the planet's circulation as a function of atmospheric metallicity and…