An extrasolar planetary system with three Neptune-mass planets

  title={An extrasolar planetary system with three Neptune-mass planets},
  author={Christophe Lovis and Michel Mayor and Francesco A. Pepe and Yann Alibert and W. Benz and François Bouchy and Alexandre C. M. Correia and Jacques Laskar and Christoph Mordasini and Didier Queloz and Nuno C. Santos and St{\'e}phane Udry and J L Bertaux and J. P. Sivan},
Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called ‘hot Neptunes’ or ‘super-Earths’ around Sun-like stars. These planets have masses 5–20 times larger than the Earth and are mainly found on close-in orbits with periods of 2–15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by… 

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