A system predicted to contain as many as seven planets orbiting a Sun-like star has been discovered 39 parsecs from the Sun — the most populous extrasolar planetary system found so far.
The planets orbit HD 10180 near the southern constellation Hydrus. Christophe Lovis at the University of Geneva in Switzerland and his team used a spectrograph at the European Southern Observatory in Chile to look for a characteristic stellar 'wobble' caused by planets tugging on their parent star. Their results suggest that five planets of a similar mass to Neptune orbit at distances of 0.06–1.4 times the Earth–Sun distance. A possible sixth planet, with a mass similar to that of Saturn, has an orbital period of about 6 years.
The seventh prospective planet could have a mass just 1.4 times that of Earth, making it the smallest extrasolar planet found so far. But with an orbital distance equivalent to just 2% of Earth's, it is likely to be a scorched world.
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An embarrassment of planets. Nature 471, 550 (2011). https://doi.org/10.1038/471550b
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DOI: https://doi.org/10.1038/471550b
