Key points are not available for this paper at this time.
The GJ 581 planetary system was already known to harbour three planets, two super-Earths planets which straddle its habitable zone. We report the detection of an additional planet -- GJ 581e -- with a minimum mass of1. 9 Mₑarth. With a period of 3. 15 days, it is the innermost planet of the and has a ~5% transit probability. We also correct our previous of the orbital period of GJ 581d (the outermost planet) with a-year alias, thanks to an extended time span and many more measurements. The period is 66. 8 days, and locates the semi-major axis inside the zone of the low mass star. The dynamical stability of the 4-planet imposes an upper bound on the orbital plane inclination. The planets be more massive than approximately 1. 6 times their minimum mass.
Mayor et al. (Thu,) studied this question.