Artist version of the exoplanetary system K2-290, with the main star K2-290 A, its two planets and the smaller accompanying star K2-290 B in the background.
Christoffer Grønne (artist)
In planetary systems, planets and their stars are generally expected to rotate in the same direction. Take, for example, our own solar system.
Our sun rotates in almost the same direction as the earth and the rest of the planets orbit, with a small six degree tilt. It was once accepted that all systems work in a similar way, but research has shown that this is not necessarily the case.
Some stars have been discovered that rotate differently from a planet orbiting them, but a recent study found that one star in the opposite direction to not one but two planets in its system.
The K2-290 system contains a total of three stars, with two planets orbiting its main star, K2-290 A. The interesting part? K2-290 A rotates at a 124 degree tilt compared to the two planets orbiting it. This means that it turns in the opposite direction.
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Maria Hjorth and Simon Albrecht from Aarhus University in Denmark made the discovery and published their findings in the journal Proceedings of the National Academy of Sciences on Monday.
The two planets orbiting K2-290 A exist on the same plane, so the direction difference becomes a little more complicated to explain.
“The fact that [the planets] seems intent, means it may not have been a dynamic violent mechanism that caused them to migrate, maybe it was the disk, “Chris Watson of Queen’s University Belfast told New Scientist. Then you have to see how you end up with the star and the planet-forming disk tilted in the first place? ‘
Albrecht and his colleagues believe that given this system has three stars, “gravitational forces of companions” are probably the cause of the unique rotation of K2-290 A. The other stars in the K2-290 system can destroy the rotation and orbits .
“The unique aspect of K2-290 is that a companion star has been detected (K2-290 B),” the study reads, “with properties that make it a good candidate for the misinterpretation of the protoplanetary disk.”