Astronomers find new planets
Astronomers are reporting the discovery of 11 new planets orbiting sun-like stars, dubbed 'exoplanets'. The international team's findings are the result of a number of high-precision radial-velocity surveys carried out at the Geneva observatory in Switzerland and the Grenoble Haute-Provence observatories in France, as well as research institutes in the USA and Israel. The method measures changes in the speed of a central star, which is caused by the changing direction of a gravitational pull from an 'unseen exoplanet'. 'Some of the new planets are unusual,' reports the European Southern Observatory (ESO), which has identified: - a two-planet system, in which one orbital period is nearly exactly twice as long as the other. 'Cases like this (referred to as 'orbital resonance') are well known in our own solar system,' says ESO; - another two-planet system with a Jupiter-like planet and a more massive planet further out; - a planet with the most elongated orbit detected so far moving between 5 and 127 million kilometres from the central star; - a giant planet moving in an orbit around its Sun-like central star that is very similar to the one of the Earth and whose potential satellites (in theory, at least) might be 'habitable'. According to ESO, there are 63 known exoplanet candidates with minimum masses below 10 Jupiter masses, and 67 known objects with minimum masses below 17 Jupiter masses. 'The present team of astronomers has detected about half of these,' it reports.