nai

Project Progress

In this task we are developing capabilities to model the atmospheres and spectra of super-Earths. This is being done with atmospheric escape, climate and radiative transfer models.

With our atmospheric escape model, we are investigating planetary upper atmospheres with a wide range of composition (from present Earth atmosphere composition to 96% CO₂) under different levels of XUV radiation. This effort will be helpful to better understand the habitability of M-star super-Earth planets. We have obtained results for atmospheres with 50% N₂ and 50% CO₂ and are exploring the parameter space (Tian, 2010). Generally speaking we found that planets in the HZ of M-stars could lose significant amount of their volatile inventory if their atmospheres are not dominated by CO₂. These results will be reported in one or two papers to be submitted by the end of 2010.

In other work, graduate student Ty Robinson made progress on a generic terrestrial atmosphere climate model. This model will allow us to generate temperature and pressure profiles for planetary atmospheres very different to the Earth, such as those for super-Earths. A new scheme has been implemented to increase the speed of the radiative transfer model that drives the climate model, and this has been tested. Work continues on coupling the surface soil and planetary boundary layer models. Graduate student Amit Misra is also modifying our radiative transfer model to allow the generation of synthetic transmission spectra for super-Earth atmospheres.