GJ 581 radial velocity curve

We report the detection of an additional planet - GJ 581e - with a minimum mass of 1.9M_{earth}_. With a period of 3.15 days, it is the innermost planet of the system and has a ~5% transit probability.

We also correct our previous confusion about the orbital period of GJ 581d (the outermost planet) with a one-year alias, benefitting from an extended time span and many more measurements. The revised period is 66.8 days, and positions the semi-major axis inside the habitable zone of the low mass star. The dynamical stability of the 4-planet system imposes an upper bound on the orbital plane inclination.