Was Planet 9 born of a different star?
A team of researchersfrom Lund University, Sweden, has run a series of computersimulations to test the likelihood that the as-of-yet undiscoveredPlanet 9 formed in the orbit of an alien star. Whilst the planet hasnot yet been directly observed, evidence of its gravitationalinfluence may have been observed perturbing the orbits of six Kuiper Belt objects, leading some to assert that Planet 9 boasts amass around 10 times that of Earth.
There are three leadingtheories on how such a planet could have come to settle in the highlyeccentric and distant orbit it is thought to traverse today. One theory holds that Planet 9 could have been a rogue planet travelling through space alone prior to being captured by our Sun's gravity. Alternatively, the planet could have formed in our Solar System, and was subsequently forced out by the influence of neighboring planets, and the gravity of a passing star.
Itis also possible that the planet may have been captured from a passing star originating from the same cluster in which our Sunwas born. As the alien star travelled close to our own, the Sun'sgravitational influence could have ripped the young exoplanet awayfrom its stellar host.
According to theresearchers behind the new study, for Planet 9 to be stolen by our Sun it must have traversed a distant orbit fromits parent star, and was therefore only tenuously bound. Furthermore,at the point of transfer, the two stars must have passed at adistance of around 150 astronomical units soas not to disturb icy bodies in the Kuiper Belt.
The team input theseconstraints and ran computer simulations using software designed tocalculate the gravitational interactions between planets and stars.In a number of the simulations Planet 9 was wrestled from the alienstar, and came to rest in a heliocentric orbit similar to the one thatthe phantom planet is thought to lay in today.
If Planet 9 is indeedan exoplanet orbiting at the fringes of our Solar System, then itcould grant astronomers the ability to make unprecedentedobservations of alien worlds that matured around distant stars.
Scroll down to see avideo of a Lund University researcher discussing the study, which has been published online in the Monthly Notices of the Astronomical Society.
Source: Lund University