Astronomers are still searching for a hypothetical “Planet Nine” in the distant reaches of our solar system, but an exoplanet 336 light years from Earth is looking more and more like the Planet Nine of its star system.
Astronomers are still searching for a hypothetical “Planet Nine” in the distant reaches of our solar system, but an exoplanet 336 light years from Earth is looking more and more like the Planet Nine of its star system.
Planet Nine, potentially 10 times the size of Earth and orbiting far beyond Neptune in a highly eccentric orbit about the sun, was proposed in 2012 to explain perturbations in the orbits of dwarf planets just beyond Neptune’s orbit, so-called detached Kuiper Belt objects. It has yet to be found, if it exists.
A similarly weird extrasolar planet was discovered far from the star HD 106906 in 2013, the only such wide-separation planet known. While much heavier than the predicted mass of Planet Nine — perhaps 11 times the mass of Jupiter, or 3,500 times the mass of Earth — it, too, was sitting in a very unexpected location, far above the dust plane of the planetary system and tilted at an angle of about 21 degrees.
The big question, until now, has been whether the planet, called HD 106906 b, is in an orbit perpetually bound to the binary star — which is a mere 15 million years old compared to the 4.5 billion-year age of our sun — or whether it’s on its way out of the planetary system, never to return.
Read more at University of California - Berkeley
Image: The 11-Jupiter-mass exoplanet called HD 106906 b, shown in this artist's illustration, occupies an unlikely orbit around a double star 336 light-years away. It may be offering clues to something that might be much closer to home: a hypothesized distant member of our solar system dubbed "Planet Nine." This is the first time that astronomers have been able to measure the motion of a massive Jupiter-like planet that is orbiting very far away from its host stars and visible debris disk. (Credit: NASA, ESA, M. Kornmesser (ESA/Hubble))
