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EarthSky // Science Wire, Space Release Date: Mar 04, 2014

Every red dwarf star has at least one planet, says new study

Red dwarfs make up at least three quarters of the stars in the universe. A new study suggests that virtually all red dwarfs have planets orbiting them.

Image credit: Neil Cook, University of Hertfordshire

Artist’s impression. Image credit: Neil Cook, University of Hertfordshire

A team of astronomers from the UK and Chile have identified three new planets as habitable-zone super-Earths among eight new planets discovered orbiting nearby red dwarf stars. Their study, to be be published in Monthly Notices of the Royal Astronomical Society suggests that virtually all red dwarfs, which make up at least three quarters of the stars in the universe, have planets orbiting them.

The research also suggests that habitable-zone super-Earth planets (where liquid water could exist and making them possible candidates to support life) orbit around at least a quarter of the red dwarfs in the sun’s own neighborhood.

These new results have been obtained from analyzing data from two high-precision planet surveys – the HARPS (High Accuracy Radial Velocity Planet Searcher) and UVES (Ultraviolet and Visual Echelle Spectrograph) – both operated by the European Southern Observatory in Chile. By combining the data, the team was able to detect signals that were not strong enough to be seen clearly in the data from either instrument alone.

To find evidence for the existence of these planets, the astronomers measured how much a star “wobbles” in space as it is affected by a planet’s gravity. As an unseen planet orbits a distant star, the gravitational pull causes the star to move back and forth in space. This periodic wobble is detected in the star’s light

The new planets have been discovered around stars between 15 and 80 light-years away and they have orbital periods between two weeks and nine years. This means they orbit their stars at distances ranging from about 0.05 to 4 times the Earth-Sun distance — 149 million kilometers (93 million miles).

These discoveries add eight new exoplanets signals to the previous total of 17 already known around such low-mass dwarfs. The paper also presents ten weaker signals for which further follow-up is necessary.

Bottom line: A study by a team of astronomers from the UK and Chile, to be be published in Monthly Notices of the Royal Astronomical Society suggests that virtually all red dwarfs, which make up at least three quarters of the stars in the universe, have planets orbiting them.

Read more about the study