Habitable Zones & Global Climate: July 2019

Young terrestrial planets can capture or outgas hydrogen-rich atmospheres with tens to hundreds of bars of H2, which persist for 100 Myrs or longer.

The GJ 357 system harbors 3 planets orbiting a bright, nearby M2.5V star at 9.44pc. The innermost planet GJ 357 b (TOI-562.01) is a hot transiting Earth-size planet with Earth-like density, which receives about 12 times the irradiation Earth receives from the Sun, and was detected using data from TESS.

Photosynthesis offers a convenient means of sustaining biospheres. We quantify the constraints for photosynthesis to be functional on the permanent nightside of tidally locked rocky exoplanets via reflected light from their exomoons.

The evolution of different forms of photosynthetic life has profoundly altered the activity level of the biosphere, radically reshaping the composition of Earth's oceans and atmosphere over time.

The Kepler data show that habitable small planets orbiting Red Dwarf stars (RDs) are abundant, and hence might be promising targets to look at for biomarkers and life. Planets orbiting within the Habitable Zone of RDs are close enough to be tidally locked.

We present a three-species multi-fluid MHD model (H+, O+ and e−), endowed with the requisite upper atmospheric chemistry, that is capable of accurately quantifying the magnitude of oxygen ion losses from "Earth-like" exoplanets in habitable zones, whose magnetic and rotational axes are roughly coincidental with one another.

Terrestrial planets covered globally with thick oceans (termed ocean planets) in the habitable zone were previously inferred to have extremely hot climates in most cases.