With the help of NASA’s Kepler space satellite, ateam of astronomers has discovered for the first time a circumbinary multiplanetary system in transit, formed by two planets that orbit around two stars. It is located 4,900 light years from Earth, in the constellation of the Swan, andstars outshine each other every 7.5 days, as explained by the researchers. One of the stars is similar to the Sun in size but with 84% of its brightness. The other is a third of the size of our star and its brightness is negligible.
The discovery shows that planetary systems can form, even survive, in the chaotic environment that is created around a binary star, as explained by Jerome Orosz, an astronomer at San Diego State University (USA), and lead author. of the investigation, which has just been published in the magazineScience.
Theinner planet (Kepler-47b) has three times the diameter of Earth, which makes it the smallest circumbinary planet in transit known to date. This planet orbits the stellar pair every 49 days. On the other hand,the exterior (Kepler-47c)is slightly larger than Neptune, orbits the two suns every 303 days, andis situated in the “habitable zone”, that is, the region around a star where a terrestrial planet could contain liquid water on its surface. However, everything points to Kepler-47c being a gas giant and therefore not fit for life. But their existence indicates that there could be others similar to Earth revolving around two stars, and that therefore this type of planets should be included in the list of candidates to find extraterrestrial life.
