Scoperto un pianeta in orbita polare intorno a due nane brune.
Il comunicato di ESO.
L’animazione:
Dall’articolo su Science:
A tilted “Tatooine planet” whose two suns aren’t stars at all
The 2M1510 system combines a set of characteristics that are individually unusual and that, in combination, make it a first of its kind. The most unusual characteristics of the 2M1510 system include the following:
The planet (estimated to have a mass ranging from that of a mini-Neptune to a Saturn) orbits not one star but two—which is to say, it orbits around a binary star system. […]
[…] the 2M1510 planet is on a polar orbit, meaning that the plane of its orbit is perpendicular to the stars’ orbit, making it one of a kind.
Technically, the two stars at the center of the 2M1510 circumbinary orbit are not stars at all. They are both a type of object known as a brown dwarf […]
The system has not two brown dwarfs, but three, in total. […]
The two brown dwarfs at the center of the circumbinary planetary system exhibit periodic eclipses as our vantage on the system from Earth has us viewing the brown dwarfs’ orbit edge-on, such that one partially blocks our view of the other every time around. Only one other eclipsing binary brown dwarf system was previously known.
Il paper su Science Advances
Evidence for a polar circumbinary exoplanet orbiting a pair of eclipsing brown dwarfs
One notable example of exoplanet diversity is the population of circumbinary planets, which orbit around both stars of a binary star system. There are, so far, only 16 known circumbinary exoplanets, all of which lie in the same orbital plane as the host binary. Suggestions indicate that circumbinary planets could also exist on orbits highly inclined to the binary, close to 90°, polar orbits. No such planets have been found yet, but polar circumbinary gas and debris discs have been observed, and if these were to form planets, then those would be left on a polar orbit. We report strong evidence for a polar circumbinary exoplanet, which orbits a close pair of brown dwarfs that are on an eccentric orbit. We use radial velocities to measure a retrograde apsidal precession for the binary and show that this can only be attributed to the presence of a polar planet.