HABEBEE: Habitability of Eyeball-Exo-Earths

Abstract

Extrasolar Earth and super-Earth planets orbiting within the habitable zone of M dwarf host stars may play a significant role in the discovery of habitable environments beyond Earth. Spectroscopic characterization of these exoplanets with respect to habitability requires the determination of habitability parameters with respect to remote sensing. The habitable zone of dwarf stars is located in close proximity to the host star, such that exoplanets orbiting within this zone will likely be tidally locked. On terrestrial planets with an icy shell, this may produce a liquid water ocean at the substellar point, one particular "Eyeball Earth" state. In this research proposal, HABEBEE: exploring the HABitability of Eyeball-Exo-Earths, we define the parameters necessary to achieve a stable icy Eyeball Earth capable of supporting life. Astronomical and geochemical research will define parameters needed to simulate potentially habitable environments on an icy Eyeball Earth planet. Biological requirements will be based on detailed studies of microbial communities within Earth analog environments. Using the interdisciplinary results of both the physical and biological teams, we will set up a simulation chamber to expose a cold- and UV-tolerant microbial community to the theoretically derived Eyeball Earth climate states, simulating the composition, atmosphere, physical parameters, and stellar irradiation. Combining the results of both studies will enable us to derive observable parameters as well as target decision guidance and feasibility analysis for upcoming astronomical platforms.

The Exosphere as a Boundary: Origin and Evolution of Airless Bodies in the Inner Solar System and Beyond Including Planets with Silicate Atmospheres

“…At perihelion, however, Mercury experience (very slow) retrograde motion for a couple of weeks, so that apparently it behaves almost like a tidally locked planet. Since the obliquity of Mercury is close to 0 it does not experience seasons, but thanks to the 3:2 resonance the same hemisphere always faces the Sun at alternate perihelion passages, producing the so-called hot poles regions at 0 • and 180 • longitudes (in opposition to the cold poles at 90 • and 270 • ), which may help in understanding the physics of "eyeball" exoplanets, which are tidally locked planets, for which tidal locking induces spatial features in the geography or composition of the planet resembling an eyeball (Angerhausen et al 2013).…”

Nicht mehr lang allein im All?

“…Abbildung zeigt die Konsequenzen anhand von Modellrechnungen: bis zu 100 Grad Differenz zwischen der konstanten Tag‐ und Nachtseite und ein permanentes Wolkensystem über den substellaren Gebieten der Planeten. Was diese Umstände für mögliches Leben und dessen Entstehung auf diesen Planeten bedeuten kann, ist Thema aktueller Forschung .…”

Geothermal heating enhances atmospheric asymmetries on synchronously rotating planets

“…The climate of a synchronously rotating planet is sometimes described using the term "eyeball Earth" to denote open water beneath the sub-stellar point, relatively clement conditions along the surface in a surrounding ring, and ice-covered conditions everywhere else all the way to the anti-stellar hemisphere (Pierrehumbert 2011;Angerhausen et al 2013). If geothermal heating can cause regions of transient warming through the enhancement of large-scale circulations, then regions of melting could create cratered pockets of ice, slowly flowing glaciers, or even standing liquid water around the anti-stellar point.…”