🌑 Of the underworld 🪐 Rocky exoplanet core

chthonian

9.9

A planet around another star that becomes a bare rock when it loses its gas

adjective
/kˈθoʊniən/

Specialized

: chtonio

Astronomers identified a chthonian planet that likely formed when its atmosphere was stripped away.

Examples

After intense stellar radiation, the gas giant's outer layers vanished, leaving a chthonian rocky core.
They studied the chthonian world to learn how atmospheric escape transforms giant planets into small, dense bodies.
The chthonian planets are fascinating to study.
Astronomers discovered a chthonian world in a distant galaxy.
Astronomers identified a chthonian planet that likely formed when its atmosphere was stripped away.
After intense stellar radiation, the gas giant's outer layers vanished, leaving a chthonian rocky core.
They studied the chthonian world to learn how atmospheric escape transforms giant planets into small, dense bodies.

Surface Forms

chthonian positive

Morphology

chthonian = chthonic (semi-transparent) = chthon + ian

The immediate morphological step (forming an adjective with '-ian' from 'chthonic') is regular and preserves the root sense.

Etymology

The word chthonian comes from the Greek root chthōn, meaning 'earth' or 'ground'. In astronomy, a chthonian planet is one whose outer gas has been removed, leaving the rocky core or 'inner earth' exposed.