Constraining the Orbits of Planet X and Nemesis

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If Planet X was out there, where would it be? This question posed by an Italian researcher turns out to be a lot more involved than you’d think. As opposed to all the 2012 idiocy hype flying around on the internet, this research is actually based on a little thing called science. By analysing the orbital precession of all the inner-Solar System planets, the researcher has been able to constrain the minimum distance a hypothetical object, from the mass of Mars to the mass of the Sun, could be located in the Solar System. As most of the astronomical community already knows, the two purveyors of doom (Planet X and the Sun’s evil twin, Nemesis) exist only in the over-active imaginations of a few misinformed individuals, not in reality…

Planet X and Nemesis are hypothetical objects with more grounding in ancient prophecy and doomsday theories based on pseudo-science. This might be the case, but Planet X came from far more rational beginnings.

The name “Planet X” was actually coined by Percival Lowell at the start of the 20th century when he predicted there might be a massive planet beyond the orbit of Neptune. Then, in 1930, Clyde Tombaugh appeared to confirm Lowell’s theory; a planet had been discovered and it was promptly named Pluto. However, as time went on, it slowly became apparent that Pluto wasn’t massive enough to explain the original observations of the perturbations of Uranus’ orbit (the reason for Lowell’s Planet X prediction in the first place). By the 1970’s and 80’s modern observation techniques proved that the original perturbations in Uranus’ orbit were measurement error and not being caused by a massive planetary body. The hunt for Planet X pretty much ended with the discovery of Pluto in 1930, but it never lived up to its promise as a massive planetary body (despite what the woefully erroneous doomsday theories say otherwise).

Now an Italian researcher has published results from a study that examines the orbital dynamics of the inner-Solar System planets, and relates them to the gravitational influence of a massive planetary body orbiting the Sun from afar.

To cut a long story short, if a massive planetary body or a small binary sibling of the Sun were close to us, we would notice their gravitational influence in the orbital dynamics of the planets. There may be some indirect indications that a small planetary body might be shaping the Kuiper Cliff, and that a binary partner of the Sun might be disturbing the Oort Cloud every 25 million years or so (relating to the cyclical mass extinctions in Earth’s history, possibly caused by comet impacts), but hard astronomical proof has yet to be found.

Lorenzo Iorio from the National Institute of Nuclear Physics in Pisa (Italy) has taken orbital data from many years of precise observations and used his computations to predict the closest possible distance at which a massive planet could orbit if it was out there.

It turns out that all the planets the mass of Mars and above have been discovered within the Solar System. Iorio computes that the minimum possible distances at which a Mars-mass, Earth-mass, Jupiter-mass and Sun-mass object can orbit around the Sun are 62 AU, 430 AU, 886 AU and 8995 AU respectively. To put this into perspective, Pluto orbits the Sun at an average distance of 39 AU.

So if we used our imaginations a bit, we could say that a sufficiently sized Planet X could be patrolling a snail-paced orbit somewhere beyond Pluto. But there’s an additional problem for Planet X conspiracy theorists. If there was any object of sufficient size (and by “sufficient” I mean Pluto-mass, I’m being generous), according to a 2004 publication by David Jewitt, from the Institute for Astronomy, University of Hawaii, we would have observed such an object by now if it orbited within 320 AU from the Sun.

Suddenly, the suggestion that Planet X will be making an appearance in 2012 and the crazy idea that anything larger than a Pluto-sized object is currently 75 AU away seems silly. Sorry, between here and a few hundred AU away, it’s just us, the known planets and a load of asteroids (and perhaps the odd plutino) for company.

Source: arXiv, Astroengine.com