A team of European scientists have discovered 45 new exoplanets, including three "super-Earths" orbiting a single Sun-like star.
Scientists detected the extrasolar planets using the HARPS instrument on the 3.4-meter telescope at the European Southern Observatory in Chile. The planets are all less than 30 times the mass of Earth and all orbit very close to their stars. It is easier to detect small planets when they orbit very close to their star, so these are the ones found first.
It was only in 2005 that the first earth-sized exoplanet was discovered and only in April 2007 that the first Earth-sized exoplanet was discovered in the so-called habitable zone (the distance from a star that provides temperatures at which liquid water is stable).
In the most recent discovery, the team found a single Sun-like star that has three super
Earths orbiting it, the smallest of which is only 4 times the mass of
Earth. The host star, HD 40307, is located 42 light-years away towards the southern Doradus and Pictor constellations. "We have made very precise measurements of the velocity of the star HD 40307 over the last five years, which clearly reveal the presence of three planets," says planet hunter Michel Mayor of the Geneva Observatory.
These planets are orbiting too close to their star to be conducive to life as we know it (they are too hot), but their existence builds the case for smaller planets being common.
This new discovery points to small planets being ubiquitous in the universe. The study looked at over 100 stars that were previously thought not to have planets. More than a third turned out to have planets slightly bigger than Earth.
There may be many other planets that current instruments cannot yet detect since they orbit too far from their stars. The current batch of planets just discovered all orbit their star sin less than 50
days. As instruments improve, we will be able to resolve
Earth-sized planets that orbit as far from their stars as Earth does, so that same sample of 100 stars might yield even more Earth-sized planets orbiting at greater distances then we can currently detect.
All this paves the way for the discovery of abundant Earth sized planets, orbiting in the habitable zone and ultimately of life in the universe. With all these planets around all these stars in all these galaxies, there has got to be some life somewhere... or so the theory goes.
Congrats to Michel Mayor, Stéphane Udry, Didier Queloz, Christophe Lovis, and Francesco Pepe (Geneva Observatory, Geneva University, Switzerland) and the whole team. They are have submitted papers on their results to the Journal of Astronomy and Astrophysics and just presented these findings at the "Extra-solar Super-Earths" conference in Nantes, France.
A Trio of Super Earths [ESO]
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See Also:__
- Hubble Detects First Organic Molecule Around Exoplanet
- Habitable Planet Discovered Outside Our Solar System
- Gliese 581c Discoverer: More Earth-Like Planets to Come
Artist Impression courtesy of European Southern Observatory
