Super-Earth planets discovered beyond solar system
Wednesday, 18 Jun 2008 12:07
Artist's impression of the trio of super-Earths
Science In Focus
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Scientists say they have discovered a triple system of 'super-Earths' around a distant star.
Super-Earths have a mass between two and ten times the Earth's mass that is less massive than that of Uranus and Neptune.
European astronomers discovered the system of super-Earths around a star named HD 40307 that lies 42 light-years away towards the southern Doradus and Pictor constellations.
Presenting the findings at the international conference Extra-Solar Super-Earths in France, the team said they also discovered 45 further potential planets with a mass below 30 Earth masses and an orbit shorter than 50 days.
They argued that this suggests one solar-like star out of three has such planets.
"Does every single star harbour planets and, if yes, how many?" said Michel Mayor from Geneva Observatory.
"We may not yet know the answer but we are making huge progress towards it."
The scientists made the super-Earth and candidate planet discoveries using the HARPS instrument at the ESO (European Organisation for Astronomical Research in the Southern Hemisphere) La Silla Observatory.
"Clearly these planets are only the tip of the iceberg," Mr Mayor commented.
"The analysis of all the stars studied with HARPS shows that about one third of all solar-like stars have either super-Earth or Neptune-like planets with orbital periods shorter than 50 days."
Researcher Stephane Udry added: "It is most probable that there are many other planets present: not only super-Earth and Neptune-like planets with longer periods, but also Earth-like planets that we cannot detect yet.
"Add to it the Jupiter-like planets already known, and you may well arrive at the conclusion that planets are ubiquitous."