_Cool Astronomy_ (http://www.csmonitor.com/Science/Cool-Astronomy) Exoplanets - as many of seven of them - spotted in newfound star system Exoplanets abound in the orbits around the star HD 10180. European astronomers have spotted at least five planets, with evidence that two others may be present.
Artists impression shows the planetary system around the Sun-like star HD 10180. (L. Calçada/ESO/AP) ____________________________________ By _Nancy Atkinson_ (http://www.csmonitor.com/layout/set/print/About/Contact-Us-Feedback) , CSMonitor.com posted August 25, 2010 at 12:35 pm EDT There is another _Sun_ (http://www.universetoday.com/16338/the-sun/) -like _star_ (http://www.universetoday.com/24184/stars/) out there with an intriguing family of _planets_ (http://www.universetoday.com/35923/planet/) orbiting about and it could be the closest parallel to our own _solar system_ (http://www.universetoday.com/15451/the-solar-system/) that astronomers have found yet. European astronomers discovered a planetary system containing at least five planets, orbiting the star HD 10180, with evidence that two other planets may be present. If confirmed, one of those would have the lowest mass ever found. “We have found what is most likely the system with the most planets yet discovered,” says Christophe Lovis, who led the team. “This remarkable discovery also highlights the fact that we are now entering a new era in _exoplanet_ (http://www.universetoday.com/42537/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_ (http://www.universetoday.com/15502/planets-in-the-solar-system/) and give us insights into the long-term evolution of the system.” To make this system even more intriguing, the team also found evidence that the distances of the planets from their star follow a regular pattern, as also seen in _our Solar System_ (http://www.universetoday.com/43827/our-solar-system/) . “This could be a signature of the formation process of these planetary systems,” said team member Michel Mayor. _IN PICTURES: Planets_ (http://www.csmonitor.com/CSM-Photo-Galleries/CSM-Galleries/Planets) HD 10180, is located 127 _light years_ (http://www.universetoday.com/56474/light-years/) away in the southern _constellation_ (http://www.universetoday.com/19516/constellations/) of _Hydrus_ (http://www.universetoday.com/20975/hydrus/) . The five confirmed planets are large, about the _size of Neptune_ (http://www.universetoday.com/22044/size-of-neptune/) — between 13 and 25 _Earth_ (http://www.universetoday.com/14367/earth/) masses —with orbital periods ranging from between six and 600 days. The planets’ distances from the star ranges from 0.06 and 1.4 times the Earth–_Sun distance_ (http://www.universetoday.com/18043/distance-to-the-sun/) . “We also have good reasons to believe that two other planets are present,” said Lovis. One would be a _Saturn_ (http://www.universetoday.com/15298/saturn/) -like _planet_ (http://www.universetoday.com/35923/planet/) (with a minimum mass of 65 Earth masses) orbiting in 2200 days. The other would be the least massive exoplanet ever discovered, with a mass of about 1.4 times that of the Earth. It is very close to its host star, at just 2 percent of the Earth–Sun distance. One “year” on this planet would last only 1.18 Earth-days. “This object causes a wobble of its star of only about 3 km/hour— slower than walking speed — and this motion is very hard to measure,” says team member Damien Ségransan. If confirmed, this object would be another example of a hot _rocky planet_ (http://www.universetoday.com/10596/large-rocky-planet-discovered/) , similar to _Corot_ (http://www.universetoday.com/59235/corot/) -7b. The team used the planet-finding HARPS spectrograph, attached to ESO’s 3.6-metre _telescope_ (http://www.universetoday.com/14424/telescopes/) at La Silla, Chile, and made observations of HD 10180 for six years. The newly discovered system of planets around HD 10180 is unique in several respects. First of all, with at least five _Neptune_ (http://www.universetoday.com/21581/neptune/) -like planets lying within a distance equivalent to the _orbit_ (http://www.universetoday.com/34665/orbit/) of _Mars_ (http://www.universetoday.com/14701/mars/) , this system is more populated than our _Solar_ (http://www.universetoday.com/47756/solar/) System in its inner region, and has many more massive planets there. Furthermore, the system probably has no _Jupiter_ (http://www.universetoday.com/14469/jupiter/) -like _gas giant_ (http://www.universetoday.com/43300/gas-giant/) . In addition, _all the planets_ (http://www.universetoday.com/36532/all-the-planets/) seem to have almost circular _orbits_ (http://www.universetoday.com/34665/orbit/) . With this new announcement, the total number of exoplanets found is 472. -- Centroids: The Center of the Radical Centrist Community <[email protected]> Google Group: http://groups.google.com/group/RadicalCentrism Radical Centrism website and blog: http://RadicalCentrism.org
