ELSI Colloquium

Dr. Cayman Unterborn (Arizona State University)
February 16, 2018

ELSI-2 Building – ELSI Lounge

Host: Christine Houser


Uncovering Earth, "Earth-like" and Not-Earth Exoplanets


Terrestrial exoplanets represent a new frontier in Earth, planetary and life science. From the discovery of sub-Mercury and super-Earth planets to the potential for magma- and water-ocean worlds, these planets are unlike anything seen in our Solar System. Furthermore, stellar observations show variations in the abundances of the major (Mg, Fe and Si) and minor (Al, Ca, Na) terrestrial planet-building elements between 10 and 400% of the Earth and Solar values. In our search for habitable planets and "Earth-2.0," we must utilize this limited set of observables to constrain an exoplanet's geodynamic and geochemical state.

In this presentation I will demonstrate the utility in finding the regions of exoplanet parameter space that produce "Not-Earths," or planets unlikely to be habitable in the same manner as Earth. While perhaps overly reductionist, this methodology is a much simpler approach than trying to find an exact Earth-analog, given that we don't completely understand the Earth. With the number of planets likely to be discovered and the scale of potential diversity of rocky planets, constraining which systems not to devote time- and cost-intensive follow up observations in our search for habitable planets is extremely useful. Finally, I will lastly highlight the need for adaptive communication channels across traditionally separate fields to uncover the boundaries between "Earth-like" and "Not-Earth-like" planets.