From Today's Astronomy & Astrophysics there were two papers from the Geneva Observatory / Grenoble team on The HARPS search for southern extra-solar planets:

• XIII. A planetary system with 3 super-Earths (4.2, 6.9, and 9.2 M_e )
• XIV. Gl 176b, a super-Earth rather than a Neptune, and at a different period

These are probably part of the 45 super-Earths tentively announced by M. Mayor last June at the Nantes conference on super-Earths. He showed radial-velocity diagrams for 45 or so planets in an impressive display, but only gave details of three at the time, while the rest were being peer-reviewed, etc. Now they're drip-feeding out.

Interestingly, this now makes 3 out of 7 super-Earths do far discovered as being around M dwarf stars, and another multiple planetary system. It looks more like the "metallicity" relation (larger and more frequent planets around more metallic stars) seems to be more true for gas giants than terrestrial planets. Super-Earths (potentially rocky planets, though heavier than Earth) look more abundant around low mass and less-metal stars.

Now, down to work examining the characteristics of these planets. Rory Barnes and colleagues at LLPL, U. of Arizona have also been looking at these three planets around HD 40307, to determine if they are super-Earths or mini-Neptunes. They have an interesting technique of modelling the tidal circularisation of the planet backwards in time, based on its current measured or estimated eccentiricity. Tidal circularisation makes the orbit of close-in planets more circular (decreasing the eccentricity, e, to zero), dumping the energy into tidal heating of the planet (and the star). Doing this for Gl 437, for example, they showed that it would be hotter than Io, with a volcanic surface and couldn't be habitable. For HD 403007b, Hence they believe the planets are not terrestrial-like, but may be more Neptune-like.

So, could these planets have oceans ?