סמינר בחוג למדעי כדור הארץ: Secondary Atmospheric Outgassing of CH4 and CO2 in Water-rich super-Earths

Abstract: 

Observations of exoplanets have shown that super-Earths are common, and water is expected to be a major bulk constituent for many of them.
We consider super-Earth sized planets which have a water mass fraction that is large enough to form an external mantle composed of high pressure water ice polymorphs and lack a substantial H/He atmosphere.
we study the transport of CH4 and CO2 in the external water ice envelopes surrounding these planets. Including CH4 and CO2 into the water matrix introduces clathrates and a new phase called filled-ice. I will discuss the possibility of ice plate tectonics and its dynamic character. When in the habitable zone the outermost condensed mantle of water planets is a global deep liquid ocean. I will discuss the ocean-atmosphere exchange of CO2. I will further present the possibility of a negative feedback mechanism, unique to water planets, helping to moderate climate. 

מארגן הסמינר: פרופ' איל חפץ