Using theHARPS spectrograph, installed in the 3.6-meter telescope of the European Southern Observatory (ESO) in La Silla (Chile), a team of astronomers has discovereda planetary system with at least five planets similar to Neptune-between 13 and 25 Earth masses- orbitingaround the star HD 10180, very similar to our Sun. In addition, the distances of the planets to their star follow a regular pattern as in the Solar System. And all the planets seem to have practically circular orbits.
As explained by Christophe Lovis, a researcher at the University of Geneva observatory in Switzerland and responsible for the study, there are good reasons to believe thatthere are two other planets present. One would be a planet similar to Saturn, with a minimum mass of 65 Earth masses, orbiting in 2,200 days. The other would bethe least massive exoplanet ever discovered, with a mass of about 1.4 times that of Earth, and would be very close to its host star, only 2 percent of the Earth-Sun distance. A “year” of this “little” planet would last only 1.18 Earth days.
For their find, the team of astronomers used the HARPS spectrograph on asix year studyduration of the star HD 10180, located 127 light years away in the southern constellation of Hydrus (the Sea Serpent). It is the “system with the largest number of planets discovered so far”, emphasizes Lovis, who also assures that “we are enteringa new era in exoplanet research: the study of complex planetary systems and not just individual planets “.
