gasdepleted

Gasdepleted is an adjective describing a state in which the gas component of a system has been significantly reduced relative to its typical, initial, or expected level. It can apply to galaxies, planetary atmospheres, circumstellar disks, and other astrophysical environments where gas mass has been diminished, influencing dynamics and evolution.

In galaxies, gas depletion can result from converting gas into stars, expelling gas through stellar feedback such as winds and supernovae, or removing gas via environmental processes like ram-pressure stripping and tidal interactions in clusters. A reduction in fresh gas accretion from the cosmic web can also prevent replenishment, reinforcing a depleted state.

In other contexts, gas depletion may occur through atmospheric escape in planets and substellar objects, driven by high-energy irradiation, or by disk dispersal in young stellar systems through photoevaporation and accretion onto the central star. In planet formation, gas is progressively locked into solids, contributing to lower gas masses in disks.

Observationally, gas depletion is inferred from low gas mass relative to stars or dust, weak emission in gas tracers such as hydrogen I (HI) or carbon monoxide (CO), or signatures of stripped gas such as tails and truncated disks. The depletion timescale, t_dep = M_gas / SFR, is used to gauge how long star formation can continue at the current rate.

See also: gas fraction, depletion time, quenching, ram-pressure stripping, photoevaporation, circumstellar disk dispersal.