Recent observations of the super-Earth GJ 1214b show that it has a relatively featureless transmission spectrum .
One suggestion is that these observations indicate that the planet ’ s atmosphere is vertically compact , perhaps due to a water-rich composition that yields a large mean molecular weight .
Another suggestion is that the atmosphere is hydrogen/helium-rich with clouds that obscure predicted absorption features .
Previous models that incorporate clouds have included their effect without a strong physical motivation for their existence .
Here , we present model atmospheres of GJ 1214b that include physically-motivated clouds of two types .
We model the clouds that form as a result of condensation in chemical equilibrium , as they likely do on brown dwarfs , which include KCl and ZnS for this planet .
We also include clouds that form as a result of photochemistry , forming a hydrocarbon haze layer .
We use a photochemical kinetics model to understand the vertical distribution and available mass of haze-forming molecules .
We model both solar and enhanced-metallicity cloudy models and determine the cloud properties necessary to match observations .
In enhanced-metallicity atmospheres , we find that the equilibrium clouds can match the observations of GJ 1214b if they are lofted high into the atmosphere and have a low sedimentation efficiency ( f _ { sed } = 0.1 ) .
We find that models with a variety of hydrocarbon haze properties can match the observations .
Particle sizes from 0.01 to 0.25 µm can match the transmission spectrum with haze-forming efficiencies as low as 1–5 % .