{
  "id": "1305.4124",
  "version": "v2",
  "published": "2013-05-17T16:09:52.000Z",
  "updated": "2013-06-14T17:42:56.000Z",
  "title": "Quantitatively Assessing the Role of Clouds in the Transmission Spectrum of GJ 1214b",
  "authors": [
    "Caroline V. Morley",
    "Jonathan J. Fortney",
    "Eliza M. -R. Kempton",
    "Mark S. Marley",
    "Channon Visscher",
    "Kevin Zahnle"
  ],
  "comment": "Revised for ApJ, Figure 8 fixed in v2",
  "categories": [
    "astro-ph.EP"
  ],
  "abstract": "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 (fsed=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 micron can match the transmission spectrum with haze-forming efficiencies as low as 1-5%.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2013-06-14T17:42:56.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "transmission spectrum",
      "observations",
      "quantitatively assessing",
      "atmosphere",
      "large mean molecular weight"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/775/1/33",
      "journal": "The Astrophysical Journal",
      "year": 2013,
      "month": "Sep",
      "volume": 775,
      "number": 1,
      "pages": 33
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1233854,
      "adsabs": "2013ApJ...775...33M"
    }
  }
}