The Diffusion Limit of Photoevaporation in Primordial Planetary Atmospheres
arXiv:2402.06933 · doi:10.3847/1538-4357/ad276f
Abstract
Photoevaporation is thought to play an important role in the early planetary evolution. In this study, we investigate the diffusion limit of X-ray and ultraviolet induced photoevaporation in primordial atmospheres. We find that compositional fractionation resulting from mass loss is more significant than currently recognized because it is controlled by the conditions at the top of the atmosphere, where particle collisions are less frequent. Such fractionation at the top of the atmosphere develops a compositional gradient that extends downward. Mass outflow eventually reaches a steady state in which hydrogen loss is diffusion limited. We derive new analytic expressions for the diffusion-limited mass loss rate and the crossover mass.
Accepted for publication in The Astrophysical Journal
References in corpus (10)
- The origins and concentrations of water, carbon, nitrogen and noble gases on Earth
- XUV-driven mass loss from extrasolar giant planets orbiting active stars
- Vertically resolved magma ocean-protoatmosphere evolution: H, HO, CO, CH, CO, O, and N as primary absorbers
- Irradiation-driven escape of primordial planetary atmospheres I. The ATES photoionization hydrodynamics code
- An analytical formalism accounting for clouds and other "surfaces" for exoplanet transmission spectroscopy
- A critical assessment of the applicability of the energy-limited approximation for estimating exoplanetary mass-loss rates
- Inefficient water degassing inhibits ocean formation on rocky planets: An insight from self-consistent mantle degassing models
- Characterization of a set of small planets with TESS and CHEOPS and an analysis of photometric performance
- The three regimes of atmospheric evaporation for super-Earths and sub-Neptunes
- The Variable Detection of Atmospheric Escape around the young, Hot Neptune AU Mic b