A World Like Ours?

Planetary System HD 10180 Discovered By HARPS Image Credit: European Southern Observatory

In a paper (pdf) published in the journal Astronomy & Astrophysics on 13 August 2010, scientists announced the discovery of a planetary system circling the star HD 10180, which is 127 light years from Earth. The extraordinary aspect of the announcement is the existence of as many as seven planets in the system. Previous exo-planetary discoveries have generally been single planets in the range of Jupiter and above. Currently, and this list will be obsolete when you read it, there are 488 exoplanets. There are 15 known systems with at least three planets, and the previous record holder has five planets, with two of them being in the Jupiter class. Christophe Lovis, lead author of the paper, stated “This remarkable discovery also highlights the fact that we are now entering a new era in exoplanet research: the study of complex planetary systems and not just of individual planets. Studies of planetary motions in the new system reveal complex gravitational interactions between the planets and give us insights into the long-term evolution of the system.” The science team is certain of the existence of five planets, whose masses are in the range of Neptune. These five planets have orbits that range from 6 to 600 days. The planets are all located in orbits around HD 10180 that are between 0.06 and 1.4 times the distance of the Earth from our Sun. This puts all five within the orbit of Mars, and the orbits of these planets are almost circular. A sixth planet is suspected, which has an orbit lasting 2,200 days, and is considerably farther away. Its mass is about that of Saturn. The seventh planet has a mass 1.4 times that of Earth, and orbits the star in 1.18 Earth days. The research team is composed of C. Lovis, D. Ségransan, M. Mayor, S. Udry, F. Pepe, and D. Queloz (Observatoire de Genève, Université de Genève, Switzerland), W. Benz (Universität Bern, Switzerland), F. Bouchy (Institut d’Astrophysique de Paris, France), C. Mordasini (Max-Planck-Institut für Astronomie, Heidelberg, Germany), N. C. Santos (Universidade do Porto, Portugal), J. Laskar (Observatoire de Paris, France), A. Correia (Universidade de Aveiro, Portugal), and J.-L. Bertaux (Université Versailles Saint-Quentin, France) and G. Lo Curto (ESO). Let us know what you think. What do you want to know about? Post a comment.