Super Earth
I was unaware that “super-earth” has a specific (although still informal) definition, roughly, a planet with a mass greater than Earth but less than a gas giant in the Sol system (i.e., less massive than Uranus or Neptune).
With improving methods and surveys, the young field of extrasolar planet studies has recently expanded into a qualitatively new domain—terrestrial (mostly rocky) planets. The first such planets were discovered during the past year and a half, judging by their measured masses of less than 10 M⊕ (“super-Earths”).
Radius and Structure Models of the First Super-Earth Planet • 2007 Feb 10 • Valencia, Sasselov, and O’Connell • The Astrophysical Journal • IOP Science
…∼5–10 M⊕ planets that some are calling “super-Earths” (such as Gliese 876d).
Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits • 2006 Dec 20 • Fortney, Marley, and Barnes • The Astrophysical Journal • IOP Science
Doppler studies and microlensing have uncovered a population of planets with minimum masses of 1.9-10 times the Earth’s mass (M_Earth), called super-Earths.
A super-Earth transiting a nearby low-mass star • 2009 Dec 16 • Charbonneau et al • arXiv.org