The most common habitable planets - atmospheric characterization of the subgroup of fast rotators

TL;DR

This paper proposes a new atmospheric characterization method for fast-rotating, potentially habitable exoplanets, especially around K and M dwarf stars, using thermal capacitance to assess atmospheric thickness and habitability.

Contribution

It introduces a novel technique based on atmospheric thermal capacitance to evaluate the habitability of fast rotator exoplanets, expanding the scope of habitability assessments.

Findings

Technique effective for planets with shorter orbital periods

Optimal targets are planets around K dwarf stars

Method enhances understanding of habitability around M dwarfs

Abstract

The current search for habitable planets has focused on Earth-like conditions of mass, volatile content and orbit. However, rocky planets following eccentric orbits, and drier than the Earth, may be a more common phenomenon in the Universe. For the subgroup of fast rotators, it is suggested that their atmospheric thermal capacitance, subject to the radiative forcing of their parent stars, may provide researchers in the near future with a simple method for the determination of a robust lower limit of atmospheric thickness. This technique, together with the spectroscopic analysis of resolved planets from their stars, both allowed by planned space and ground-based observatories with thermal IR capabilities, would enable us with a better understanding of the habitability of this class of planets. The technique works better for smaller orbital periods, but since the tidal lock radius of M dwarfs encompasses their HZ, the optimum targets would be planets around K dwarf stars. The atmospheric thermal capacitance could also expand the range of Habitable Zones for shorter orbits, particularly for planets around M dwarf stars, since the higher frequency of the periodic radiative forcing dampens the surface temperature variation considerably.