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Radius Gap

All articles tagged with #radius gap

space4 days ago•12 min saved

Sub-Neptunes: The Galaxy’s Most Common Planet Type, Yet Absent from Our Solar System

Sub-Neptunes—planets larger than Earth but smaller than Neptune—emerge as the Galaxy’s most common type, yet no such world orbits the Sun. Their interiors can range from rocky cores with thin hydrogen envelopes to water-rich or thick atmospheres, and similar bulk densities can hide very different compositions. A radius gap between roughly 1.5–2 Earth radii helps constrain formation, but atmospheric data are still muddled by clouds and hazes, making interiors hard to pin down. The upcoming JWST and next-generation telescopes should sharpen atmospheric measurements and population studies, shedding light on planet formation and why our Solar System is missing this dominant class.

via Space Daily|

#exoplanets #gj1214b #jwst

science1 month ago•72 min saved

Earth-like cores may be the oddity in the galaxy's most common planets

A new study argues that the galaxy's most common planets—sub-Neptunes—may not have Earth-like layered interiors with a distinct metallic core and silicate mantle. If these planets accrete more than about 1% hydrogen by mass, hydrogen, iron, and silicate can mix into a single, homogeneous interior, changing how they cool, hold onto atmospheres, and evolve their radii. This could explain features like the radius gap and how radii relate to orbital period, and it offers testable predictions for JWST observations, though the model rests on extrapolations of material behavior under extreme pressures. In short, Earth-like cores might be the exception rather than the rule in the galaxy.

via Space|

#exoplanets #hydrogen-miscibility #planetary-interiors