The planet was discovered by an Observatory of Geneva team led by Michel Mayor, using the HARPS instrument on the European Southern Observatory 3.6 m (140 in) telescope in La Silla, Chile.

Mayor's team employed the radial velocity technique, in which the orbit size and mass of a planet are determined based on the small perturbations it induces in its parent star's orbit via gravity.

[2] Gliese 581e completes an orbit around its parent star in 3.15 days.

[3] Although scientists think it probably has a rocky surface similar to Earth, it is also likely to experience intense tidal heating similar to (and likely more intense than) that affecting Jupiter's moon Io.

[6] Media related to Gliese 581 e at Wikimedia Commons Discovery of smallest exoplanet yields 'extraordinary' find at Wikinews