Hycean worlds Archives

Model transmission spectrum of our canonical Hycean world K2-18 b. The model spectrum with all the molecules included is shown in grey. The spectra with the individual contributions of the different molecular species are shown as denoted in the legend. The synthetic JWST observations corresponding to the full model are shown as the gold-centered black points with error bars binned to a resolution of R= 40. The observations include one transit with NIRISS SOSS, three transits with NIRSpec G395H and two transits with MIRI LRS, as discussed in section 4. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Chemical Conditions On Hycean Worlds

by Keith CowingJune 26, 2023June 26, 2023

Traditionally, the search for life on exoplanets has been predominantly focused on rocky exoplanets. Hycean worlds are a class of habitable sub-Neptunes with planet-wide oceans and H2-rich atmospheres. Their broad […]

Surface temperature as a function of incoming instellation for different hydrogen-helium inventories. The introduction of layers with convective inhibition when the moisture content at the bottom of the atmosphere (BOA) is high enough (orange region) causes a rapid increase in surface temperature (and moisture content). Once the bottom of the atmosphere is pure steam (pink region), the atmosphere becomes optically thick and increasing surface temperature is no longer linked with an increase in cooling, causing a runaway state. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

The Runaway Greenhouse Effect on Hycean Worlds

by Keith CowingApril 11, 2023April 11, 2023

Hycean worlds are a proposed subset of sub-Neptune exoplanets with substantial water inventories, liquid surface oceans and extended hydrogen-dominated atmospheres that could be favourable for habitability.