MEarth-1b?

With the realization that rocky planets may well be plentiful around M-dwarf stars, a number of ground-based surveys have started regular monitoring of a significant number of these objects as e.g. the M-Earth Project (Irwin et al. 2008) with the expectation that around these small stars, super-Earth (or smaller) planets should be detectable. Given the low luminosity of the star, the habitable zones in these objects are close in, and it is likely that ground based surveys could well be able to detect planets in these regions within a few years. The faintness of typical M-dwarf host stars will make detailed characterization follow-up really challenging, even with the future giant telescopes or with JWST. Enthusiastically, a first discovery from the M-Earth project (still non public, to appear in Nature, in Dec 2009) is revealing a super-Earth with a mean density very different from the one of CoRoT-7b despite similar masses (Fig. 2.4).

Information from transits.
Transit observations have led to some remarkable results. We have found almost a factor of two variations in the size of giant planets of similar masses (with unexplained cause) and begun to study their internal structure through comparison of their bulk density with theoretical models. Although still based on small statistics, the situation seems to be similar for super-Earths, for which the CoRoT and M-Earth candidates present fairly different radii (1.7 and 2.7 Earth radius) despite estimates of their masses that are not very different (4.8 and 5.7 Earth masses, respectively). This demonstrates once more the variety of possible outcome from planet formation processes. Recently, we also have started to gather hints about the orbital dynamical histories of transiting planets through the Rossiter-McLaughlin and Kozai effects. Very surprisingly, it turns out that about 1/3 of the known transiting planets are misaligned (not crossing the stellar disk perpendicularly of the star rotation axis; Collier-Cameron, Porto conf. 2009), a strong indication of stockastic processes during the planet formation or evolution.

Stalker wrote:Have you got the orbital characteristics?

Is this planet habitable?