Three Earth-like planets discovered orbiting nearby star; Potentially habitable
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An international team of astronomers has announced the discovery of three super-Earth planets orbiting the star Gliese 667C. These planets are located in the habitable zone around the star where liquid water could exist, raising the possibility that living organisms could be present there.
The team of astronomers, led by Guillem Anglada-Escudé of the University of Göttingen in Germany and Mikko Tuomi of the University of Hertfordshire in the UK, combined fresh observations of the star Gliese 667C with existing data from the High Accuracy Radial velocity Planet Searcher (HARPS) at the European Southern Observatory’s (ESO) 3.6-meter telescope in Chile to reveal a system of at least six orbiting planets. Three of these planets are potentially habitable super-Earths–more massive than Earth but less massive than gas giants like Uranus or Neptune. Reportedly, this is the first time that three super-Earths have been observed orbiting within the habitable zone of the same system.
“The number of potentially habitable planets in our galaxy is much greater if we can expect to find several of them around each low-mass star,” said co-author Rory Barnes of the University of Washington, Seattle, in a statement released today (June 25) by the ESO. “Instead of looking at 10 stars to look for a single potentially habitable planet, we now know we can look at just one star and find several of them.”
The star Gliese 667C is located only about 22 light-years from Earth in the constellation Scorpius the Scorpion. It is part of a triple-star system known as Gliese 667 (GJ 667). Previous studies of Gliese 667C found three planets orbiting it, with one deemed to be in the habitable zone. The new evidence, obtained with HARPS observations along with data from the ESO’s Very Large Telescope (VLT), the W.M Keck Observatory, and the Magellan telescopes, suggests that there may be as many as seven planets circling the star.
According to the ESO, numerous compact systems around Sun-like stars exist in our Milky Way. Planets orbiting close to their host star are extremely hot and probably uninhabitable. However, the situation is different for cooler, dimmer stars like Gliese 667C. That system is the first example where such a low-mass star has been observed to host several potentially rocky planets in the habitable zone.
Gaspare Lo Curto, the ESO scientist responsible for HARPS, stated that the exciting new discovery was largely made possible by the power of HARPS and its software. “It is very good to also see several independent research groups exploiting this unique instrument and achieving the ultimate precision,” he said. According to co-author Anglada-Escudé, the new discovery highlights the value of re-analyzing data and combining results from different teams using different telescopes.
The team’s findings are detailed in the June 7 issue of the journal Astronomy and Astrophysics.
