Since Pluto was downgraded to a dwarf planet in 2006 by the International Astronomical Union (IAU), there are officially eight planets in our Solar System. But some scientists still consider Pluto a planet. The NASA administrator Jim Bridenstine also believes that the tiny cosmic object from the Solar System’s edges should be regarded as a planet again.
With or without Pluto, many scientists suspect that there’s another planet out there within the dark outskirts of the Solar System that wasn’t discovered yet. Due to the huge distance from the Sun and therefore lack of enough illumination, telescopes can’t see the planet directly if it really exists, but scientists don’t lose hope just yet.
HD106906 b enters the cosmic scene
HD106906 b was discovered in 2013 with the help of the Magellan Telescopes from the Las Campanas Observatory in the Atacama Desert. Scientists slowly figured out that they’re not dealing with just another exoplanet, and there are several strong reasons for that claim. A new study led by Meiji Nguyen of the University of California, Berkeley, reveals a deeper insight into the HD106906 b exoplanet. The object is eleven times more massive than Jupiter, and it’s located on an unlikely orbit around a binary star that’s about 336 light-years away from us. But above all, the exoplanet could be offering clues to the long-sought and hypothetical ‘Planet Nine’ from our Solar System.
A cold and lonely world
HD106906 b is located very far away from the binary stars it revolves around: about 730 times the distance between the Earth and the Sun. It’s hard to believe that there could be any life forms remaining alive on the exoplanet at such distance. Furthermore, one complete rotation of HD106906 b around the host stars lasts for 15,000 years.
Scientists also discovered that the exoplanet has an extreme orbit that is very elongated, inclined, and external to a dusty disc of debris that surrounds the two host stars. Nguyen declared:
To highlight why this is weird, we can just look at our own Solar System and see that all of the planets lie roughly in the same plane,
He also added:
It would be bizarre if, say, Jupiter just happened to be inclined 30 degrees relative to the plane that every other planet orbits in. This raises all sorts of questions about how HD 106906 b ended up so far out on such an inclined orbit.
SciTech Daily also published an artist’s impression of the HD106906 b exoplanet:
But how is it possible that the peculiar exoplanet is so far away from its host stars, and why does it have such a strangely inclined orbit? Luckily enough, there’s a theory to bet on.
HD 106906 b formed much closer to its host stars
The exoplanet initially formed much closer to its host stars, about three times the distance between Earth and the Sun. Later on, the exoplanet’s orbit started to decay. Drag within the system’s gas disc was the culprit, forcing the orbit to migrate inward toward the two host stars. The gravitational forces from the two stars then kicked the planet out onto an eccentric orbit. What happened next is that a star passed very close to this system and stabilized the exoplanet’s orbit. As weird as this theory sounds, it’s the best bet scientists have for what could have caused the conditions of the HD 106906 b exoplanet.
The resemblance with “Planet Nine”
The scenario described above can also explain what may have caused the hypothetical Planet Nine to end up within the outskirts of the Solar System. If Planet Nine truly is there somewhere, it may have formed in the inner Solar System and was further kicked out after interacting with Jupiter.
Paul Kalas of the University of California, Berkeley, who’s also a member of the scientific team involved in the new study, explains:
It’s as if we have a time machine for our own Solar System going back 4.6 billion years to see what may have happened when our young Solar System was dynamically active and everything was being jostled around and rearranged.
The new study was published in The Astronomical Journal.