March 4, 2014
Astronomers Discover New Super Earths Orbiting Red Dwarf Stars
Lee Rannals for redOrbit.com - Your Universe Online
A team of astronomers from the UK and Chile have discovered three new planets classified as Super Earths.
The planets are part of a group of eight new planets discovered orbiting nearby red dwarf stars. This study shows that virtually all red dwarfs have planets orbiting around them.
Astronomers used the High Accuracy Radial Velocity Planet Searcher (HARPS) and Ultraviolet and Visual Echelle Spectrograph (UVES) telescopes for the study. The team combined data from these surveys to help detect signals that were not strong enough to be seen clearly in data from either instrument alone.
“We were looking at the data from UVES alone, and noticed some variability that could not be explained by random noise. By combining those with data from HARPS, we managed to spot this spectacular haul of planet candidates,” Dr Mikko Tuomi, from the University of Hertfordshire’s Centre for Astrophysics Research and lead author of the study published in the Monthly Notices of the Royal Astronomical Society, said in a statement.
The research suggests that habitable zone super-Earths orbit around at least a quarter of the red dwarfs in the Sun’s neighborhood. Red dwarfs make up at least three quarters of the stars in the Universe.
“We are clearly probing a highly abundant population of low-mass planets, and can readily expect to find many more in the near future – even around the very closest stars to the Sun,” Tuomi said.
In order to find evidence for these planets, astronomers measure how much a star “wobbles” in space as a result of a planet’s gravity tugging on it. These wobbles help scientists determine a planet’s mass and orbit.
The team used Bayes' rule of conditional probabilities along with a technique to filter out excess noise in the measurements in order to discover these exoplanets.
“This result is somewhat expected in the sense that studies of distant red dwarfs with the Kepler mission indicate a significant population of small radius planets. So it is pleasing to be able to confirm this result with a sample of stars that are among the brightest in their class,” Professor Hugh Jones, also from the University of Hertfordshire, said in a statement.
The planets sit between 15 and 80 light years away from Earth and have orbital periods between two and nine years.