21 Jun 2013
The Titius-Bode Law of orbital distances have been revamped and applied to discovered exo-planets . A good fit was found . An Intra-Mercurial is deduced .
An old discarded empirical “Law” has been picked up , dusted off , revamped and is now used to find Solar and exo-Solar planets .
The Intra-Mercurials can be seen in para 2 below .(0.188888 AU) . Possible shepherd planets .
1.A summation :
A handy guide to planetary parking spots
17 April 2013 by Jacob Aron
Magazine issue 2913. Subscribe and save
Read more: Click here to read the original, longer version of this story
NEED somewhere to park your planet? You won't have to circle the galaxy for long: up to two-thirds of planetary systems have empty spaces where an extra world could comfortably reside.
The gravitational tug-of-war between a star and its orbiting planets means that the worlds must be spaced at particular distances or else their orbits become unstable. The planets will then wobble around until some collide or are ejected.
Our current understanding of planetary formation suggests that most stable systems should be filled to capacity. "In the solar system, we know that's not quite true, because we know that in between Mars and Jupiter you could put another planet," says Sean Raymond at the Laboratory of Astrophysics of Bordeaux in France. Some theories say we started out with more worlds, but jostling with Jupiter caused some to be ejected 4 billion years ago.
Julia Fang and Jean-Luc Margot at the University of California, Los Angeles, wanted to find out whether other planetary systems are full, or if they also have unoccupied but stable orbital slots in between their planets.
The pair simulated millions of systems in a variety of orbital configurations and compared their models with real systems seen by NASA's Kepler space telescope. This told them which of their modelled systems are spaced right to be stable. The duo then checked whether these systems had orbital slots going spare, by sticking an extra planet in between two existing ones and modelling how the orbits evolved over 100 million years. Would it cause a collision or ejection?
Fang and Margot discovered that about a third of the stable two- and three-planet systems they modelled would go haywire if they added a world, rising to nearly half for four-planet systems (The Astrophysical Journal, doi.org/k6s). That means the remaining majority of systems have empty stable zones, although that proportion could be revised downwards as more systems are discovered.
Pinning down spaces between known exoplanets might be useful for finding worlds that have so far avoided detection, says Raymond. "You can say, 'We think there should be a planet on this orbit, go look for it'," he says.
In fact, two other astronomers have found seemingly unoccupied slots that may in fact harbour potentially habitable worlds. Their method involves reviving the Titius-Bode relation, a rough mathematical rule for predicting planetary spacing. Developed in the late 1700s, the rule initially worked well for our solar system but fell out of favour when it conflicted with the discovery of Neptune in 1846.
Charles Lineweaver and Timothy Bovaird of the Australian National University in Canberra have now applied the equation to 64 other known systems that contain multiple planets or planet candidates. They found that it works as well as – or better than – it does for the solar system in 89 per cent of cases (arxiv.org/abs/1304.3341). The rule also suggested unoccupied but stable orbital slots in several systems discovered by Kepler, including two in the life-friendly zone around the star KOI-490.
The team reckons these spaces contain as-yet-undetected planets. But if some systems have a truly empty slot, could a sufficiently advanced civilisation build a planet and park it in orbit? "Gravitationally it would certainly work out, I'm just not sure about the logistics," says Fang.
This article appeared in print under the headline "Handy guide shows planet parking slots"
2. Bit more detail
They predict a trans Plutonian called Eris .
But extrapolating from eyeballing and general principles , there seems to be room for intra-Mercurial at 0.188888 AU (=x^(-1.6666))
radius of the sun = 0.00464913034 Astronomical Units
It seems that the sun might have shepherd planets close in .
Ideal place for a Solar powerstation or observatory , especially if there are Trojans .
Happy orbits !