New super-earth

Print edition : November 30, 2012

Artist's conceptualisationof the new super-earth planet and its star.-BY SPECIAL ARRANGEMENT

AN international team of astronomers, led by Mikko Tuomi, University of Hertfordshire, U.K., and Tuorla Observatory of the University of Turku, Finland, and Guillem Anglada-Escude, University of Goettingen, Germany, has discovered a new super-earth planet that may have an earth-like climate and be able to support life.

The new planet, designated HD 40307g, exists in the habitable zone of a nearby star known as HD 40307 and is part of a six-planet system. The system was previously thought to contain three planets in orbits too close to the star to support liquid water. Subsequently, the researchers identified three more planets in orbit.

The research team employed new data analysis techniques, including the use of wavelength as a filter, to reduce the influence of stellar activity on the signal from this star. This significantly increased sensitivity to reveal the three new planets, all super-earth candidates, around the star.

Of the new planets, the one of greatest interest is the one with the outermost orbit from the starwith a mass at least seven times that of the earth. Its orbit around its star is at a similar distance to earths orbit around the sun, so the energy it receives is similar to what the earth receives from the sun, increasing the probability of it being habitable. This is why the presence of liquid water and stable atmospheres to support life is possible. More importantly, the planet is likely to be rotating on its own axis as it orbits around the star, creating a daytime and night-time effect on the planet, which could create an Earth-like environment.

Earlier this year, the Kepler spacecraft found a planet, Kepler-22b, with a similar orbit. However, it is located 600 light years from earth, whereas HD 40307g is much closer, only 44 light years away.

R. Ramachandran
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