Press release: Scientists discover new super-Earth

Nr. 212/2012 - 08.11.2012

Conditions on planet may be just right to support life

(pug) An international team of astronomers led by the Universities of Hertfordshire and Göttingen has discovered a new super-Earth with conditions that may be just right to support life. The new planet exists in the habitable zone of a nearby Sun-like star 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. By avoiding fake signals caused by stellar activity, the researchers identified three new super-Earth planet candidates also in orbit. Their results were published in Astronomy and Astrophysics.

The Sun-like star HD 40307 is located 42 light years from Earth in the constellation Pictor. It hosts six planets, so-called super-Earths, with a mass of up to ten times that of the Earth and possibly a solid surface. “Planetary systems with multiple super-Earths have been observed several times”, says Dr. Guillem Anglada-Escudé from Göttingen University’s Institute of Astrophysics. Three of the six planets are so close to their central star that their surface temperatures are too hot to allow the existence of water in liquid form.

“Of the new planets, the one of greatest interest is the one with the outermost orbit from the star”, says Prof. Dr. Ansgar Reiners, also from Göttingen University’s Institute of Astrophysics. This planet orbits around the host star at a similar distance to Earth’s orbit around our Sun. Therefore, it receives a similar amount of energy from the star as the Earth receives from the Sun. “It has a mass at least seven times the mass of the Earth”, says Dr. Anglada-Escudé. “It is a perfectly quiet old dwarf star, so there is no reason why such a planet could not sustain an Earth-like climate.”

The fact that the planet receives a similar amount of energy from the star as the Earth receives from the Sun makes the presence of liquid water and stable atmospheres to support life possible. Even more importantly, the planet is likely to be rotating on its own axis as it orbits around the star: This creates a day-and-night-time effect on the planet that might be important for a stable Earth-like environment.

Original publication: Mikko Tuomi et al. Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307. Astronomy & Astrophysics, http://star-www.herts.ac.uk/~hraj/hd40307/hd40307_final.pdf, reference number: AA/2012/20268.

Contact:
Dr. Guillem Anglada-Escudé
Georg-August-Universität Göttingen
Faculty of Physics – Institute of Astrophysics
Friedrich-Hund-Platz 1, 37077 Göttingen
Phone +49 551 39-9988
Email: anglada@astro.physik.uni-goettingen.de
Web: www.astro.physik.uni-goettingen.de

Prof. Dr. Ansgar Reiners
Georg-August-Universität Göttingen
Faculty of Physics – Institute of Astrophysics
Friedrich-Hund-Platz 1, 37077 Göttingen
Phone +49 551 39-13825
Email: areiners@astro.physik.uni-goettingen.de
Web: www.astro.physik.uni-goettingen.de