By continuing to use this website, you are giving consent to our use of cookies. For more information on how ESO uses data and how you can disable cookies, please view our privacy policy. A European team of astronomers [1] has discovered the lightest known planet orbiting a star other than the sun an "exoplanet".
The new exoplanet orbits the bright star mu Arae located in the southern constellation of the Altar. It is the second planet discovered around this star and completes a full revolution in 9. With a mass of only 14 times the mass of the Earth, the new planet lies at the threshold of the largest possible rocky planets, making it a possible super Earth-like object. Uranus, the smallest of the giant planets of the Solar System has a similar mass.
However Uranus and the new exoplanet differ so much by their distance from the host star that their formation and structure are likely to be very different. It is another clear demonstration of the European leadership in the field of exoplanet research.
Since the first detection in of a planet around the star 51 Peg by Michel Mayor and Didier Queloz from the Geneva Observatory Switzerland , astronomers have learned that our Solar System is not unique, as more than giant planets orbiting other stars were discovered mostly by radial-velocity surveys.
This fundamental observational method is based on the detection of variations in the velocity of the central star, due to the changing direction of the gravitational pull from an unseen exoplanet as it orbits the star.
