«The crowd» of planets in the habitable zone

The triple star system Gliese 667 (GJ 667) visible in the constellation Scorpius, and located at a distance 22 light years, is of particular interest to astronomers because it is composed of one of the closest star around which the planet turns, mass comparable to Earth.

Previous studies of one of the components of the system, the designation Gliese 667S showed that he has three planet-satellite. One of them — GJ 667S with — receives from its star by only 10% less energy than the Earth receives from the Sun, which makes it possible to exist on its surface liquid water. Recently, a team of astronomers led by Guillem Anglada-escudos from the University of Gottingen (Guillem Anglada-Escude, Georg-August — Universitat, Gottingen) and Mikko Tuomi from the University of Hertfordshire (MіkkoTiotі, University of Hertfordshire) has decided to investigate the system in more detail.

For existing observational data, scientists have added the new results, obtained using a spectrograph HARPS, mounted on a 3.6-meter reflector of the European Southern Observatory (ES0), as well as the Keck telescope in Hawaii and the Magellan telescope Very Large Telescope (VLT ES0). The analysis of the totality of the data led to the conclusion that the star GJ 667S actually seven planets, the orbits of the three of them lie within the «habitable zone.» In view of the newly discovered objects, this area is filled with «to failure» — other stable orbits inside it, which could handle any more of the planet, does not exist.

It’s safe to say that the three discovered exo — planets belong to the class of «super — Earths»: they are heavier than the Earth, but «do not reach» by weight to water giants — such as Uranus or Neptune. Interestingly, the «habitable zone» GJ 667S is very small (much smaller than, for example, in the solar system); Nevertheless, it is the first time found more than one of the planet — like object. And they are more likely to consist of stony rocks, like our planet.

It is now clear that in the Milky Way, there are many compact planetary system around the Sun-like stars. In such systems the planets orbit close to their heavenly bodies, and because of the very high surface temperature, they are unlikely to be inhabited. But with the cooler and dimmer stars — such as Gliese 667S — is not the case. In their case, a «zone of life» often lies within the sphere whose radius is comparable to the major axis of the orbit of Mercury, which means it is much closer to the central body.

«If every low-mass stars, you can expect to find more potentially habitable planets, the total number of such objects in the Milky Way is much longer than anticipated. Previously, to find a potentially habitable planet, we explored a dozen stars, but now we know that it is possible to find several such planets around a single star, «- commented on the results of studies of the participant Rory Barnes of the University of Washington (Rory Barnes, University of Washington. Seattle).

This is a remarkable discovery was made largely due to the efficiency of HARPS and designed for the receiver of the software. He played a huge role, and archive data ES0. New achievement once again reminds us how important it is to re-examine already processed to produce observations and synthesis of data obtained by different groups of experts using different telescopes.

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