Geoastronomy: Rocky planets as the Lavosier-Lomonosov Bridge from the non-living to the living world

TL;DR

This paper introduces Geoastronomy, a multidisciplinary approach combining geology and astronomy to understand how galactic chemical evolution influences rocky planets' potential to host life, emphasizing the importance of elemental composition and thermal regimes.

Contribution

It proposes a new interdisciplinary framework, Geoastronomy, to study the influence of galactic chemical evolution on rocky planets' habitability and composition.

Findings

Galactic chemical evolution affects planetary elemental abundances.

Planetary composition influences atmosphere and hydrosphere development.

Age and thermal regimes of planets are key to habitability.

Abstract

Life on Earth emerged at the interface of the geosphere, hydrosphere and atmosphere. This setting serves as our basis for how biological systems originate on rocky planets. Often overlooked, however, is the fact that the chemical nature of a rocky planet is ultimately a product of galactic chemical evolution. Elemental abundances of the major rock-forming elements can be different for different stars and planets formed at different times in galactic history. These differences mean that we cannot expect small rocky exoplanets to be just like Earth. Furthermore, age of the system dictates starting nuclide inventory from galactic chemical evolution, and past, present and future mantle and crust thermal regimes. The bulk silicate mantle composition of a rocky planet modulates the kind of atmosphere and hydrosphere it possesses. Hence, the ingredients of a rocky planet are as important for its potential to host life as proximity to the so-called habitable zone around a star where liquid water is stable at the surface. To make sense of these variables, a new trans-disciplinary approach is warranted that fuses the disciplines of Geology and Astronomy into what is here termed, Geoastronomy.