eso0915 — Science Release Lightest exoplanet yet discovered 21
April 2009 Well-known exoplanet researcher Michel Mayor today
announced the discovery of the lightest exoplanet found so far.
The planet, “e”, in the famous system Gliese 581, is only about
twice the mass of our Earth. The team also refined the orbit of
the planet Gliese 581 d, first discovered in 2007, placing it
well within the habitable zone, where liquid water oceans could
exist. These amazing discoveries are the outcome of more than
four years of observations using the most successful low-mass-
exoplanet hunter in the world, the HARPS spectrograph attached
to the 3.6-metre ESO telescope at La Silla, Chile. “The holy
grail of current exoplanet research is the detection of a rocky,
Earth-like planet in the ‘habitable zone’ — a region around the
host star with the right conditions for water to be liquid on a
planet’s surface”, says Michel Mayor from the Geneva
Observatory, who led the European team to this stunning
breakthrough. Planet Gliese 581