Updates on Kepler-22 b during the First Kepler Science Conference

Post date: Dec 06, 2011 2:28:24 PM

Dec05: The recent confirmation of Kepler-22 b (KOI-087) does not qualify as a potential habitable exoplanet in the Habitable Exoplanets Catalog. It is in the habitable zone of the star but it is also too big and classified here as a Warm Neptunian. Most of the interesting exoplanets in our catalog are Kepler objects too just waiting for confirmation as Kepler 22b did today.

Dec06: This is our basic habitability analysis for Kepler-22 b. We have conflicting values for the radius (and proposed mass) from various sources (Kepler database have 2.38 Earth Radii) but we will correct this with the paper. In either case the ESI is less than Mars and classified as a Warm Neptunian non-habitable, although very close to a superterran size. "Surface temperature" is good (~40°C) but this is probably the temperature of the top water clouds layers. Venus has nice temperatures in the top clouds layers too, but lead-melting temperatures at the surface. Still, this is an interesting object for future observations. One more thing... When we updated the table of the confirmed exoplanets, we realized that this is the first Warm Neptunian of the confirmed exoplanets, another milestone.

Update#1: We modeled now a best case scenario using a mass-radius relationship that assumed an ocean planet and things changed a lot. Without mass it is very difficult to assess the habitability of Kepler-22 b. More observations will be needed to clarify its habitability status. It is so close to a transition point between superterrans and neptunians, but here it is, Kepler-22 b as a habitable planet.

This interpretation is for an oceanic planet with a thick cloud layer and no continents. It is hard to believe how an exoplanet will get so much water in the inner region of the snow line, but migrations are a possibility.

Update#2: The previous images shows two versions for Kepler-22 b, the worst case scenario as a superdense Warm Neptunian exoplanet and the best scenario as a habitable Warm Superterran ocean planet. It is hard to tell which version is correct and this only tell us that we need more observations of this exoplanet. We will evaluate it in more detail in the followings days to decide if it goes into the catalog.

Dec08: The paper for Kepler-22 b is now available in ArXiv but it briefly addressed its habitability. Probably a follow-up paper will do so. Also, the new Kepler candidates should be soon in the MAST Archives.

Update#1: The SPH of the picture above of Kepler-22 b, as an oceanic Warm Superterran, was updated. Although Kepler-22 b modeled surface temperature suggests a high SPH value, this is a habitability metric for land areas only and therefore zero for ocean planets (thanks to @andrewrushby for spotting this confusing value). Even an SPH for oceans exoplanets (now considering phytoplankton life instead of vegetation) will be zero or very low independently of temperature. Here are some scientists opinions on the habitability of Kepler-22 b.