Circumbinary Habitability Niches

TL;DR

This paper proposes the Binary Habitability Mechanism (BHM), suggesting that certain binary star systems can create favorable conditions for life by reducing stellar activity and aiding water retention on circumbinary planets.

Contribution

It introduces the BHM concept, demonstrating how specific binary star configurations can enhance habitability by mitigating stellar activity and supporting water retention.

Findings

High-quality habitable niches exist for certain binary star combinations.

BHM operates effectively for specific periods and eccentricities.

Conditions may allow life on planets and moons in binary systems.

Abstract

Binaries could provide the best niches for life in the galaxy. Though counterintuitive, this assertion follows directly from stellar tidal interaction theory and the evolution of lower mass stars. There is strong evidence that chromospheric activity of rapidly rotating young stars may be high enough to cause mass loss from atmospheres of potentially habitable planets. The removal of atmospheric water is most critical. Tidal breaking in binaries could help reduce magnetic dynamo action and thereby chromospheric activity in favor of life. We call this the Binary Habitability Mechanism (BHM), that we suggest allows for water retention at levels comparable to or better than Earth. We discuss novel advantages that life may exploit, in these cases, and suggest that life may even thrive on some circumbinary planets. We find that while many binaries do not benefit from BHM, high quality niches do exist for various combinations of stars between 0.55 and 1.0 solar masses. For a given pair of stellar masses, BHM operates only for certain combinations of period and eccentricity. Binaries having a solar-type primary seem to be quite well suited niches having wide and distant habitable zones with plentiful water and sufficient light for photosynthetic life. We speculate that, as a direct result of BHM, conditions may be suitable for life on several planets and possibly even moons of giant planets orbiting some binaries. Lower mass combinations, while more restrictive in parameter space, provide niches lasting many billions of years and are rich suppliers of photosynthetic photons. We provide a publicly available web-site (\href{http://bit.ly/BHM-calculator}{http://bit.ly/BHM-calculator}, \href{http://bit.ly/BHM-calculator-mirror}{http://bit.ly/BHM-calculator-mirror}), which calculates the BHM effects presented in this paper.