Living on the Edge: The Effects of a Surface on Atmospheric Circulation and Emission Features for 1.5 REarth Planets
Abstract
It is well known that planets between the radius of Earth and Neptune have been the most commonly detected to-date. Without a direct comparison in our Solar System, we are left without an immediate understanding of what the compositions of these types of planets are. To classify them, we have traditionally turned to mass-radius relations and composition curves in order to determine the likelihood of such a planet being rocky or gaseous. While previous work has determined that at a radius of approximately 1.5 times that of Earth a planet is equally likely to be either terrestrial or gaseous, we cannot expect that any transition between these two compositions will be a sharp cut-off due to the wide range of possible composition curves that can agree with a given density measurement for a planet of this size. Therefore, we must turn to alternative methods to classify these planets when they fall in this regime and when aerosols limit our ability to break this degeneracy by measuring atmospheric composition directly through transmission and emission spectroscopy. In this talk we present one such new method using 3D general circulation models of 1.5 Earth radii planets. With this method, we study the effects of a surface on observable quantities such as equator-to-pole differences in emitted and reflected light with an eye on detecting the presence of a surface through secondary eclipse mapping with future instrumentation. In this talk we will present our updated GCM, verified on the circulations of Earth and Neptune, before discussing our modeling choices and results for our transition planets. Finally, we discuss the comparison of models with surfaces at various pressures and without surfaces while exploring the prospects of detecting a surface through secondary eclipse observations in the near future.
- Publication:
-
AAS/Division for Extreme Solar Systems Abstracts
- Pub Date:
- August 2019
- Bibcode:
- 2019ESS.....432711M