Easy Orbits
Andre Willers
21 Jun 2013
Synopsis :
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 .
Discussion :
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"
Xxxxxxxxxxxx
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 .
Xxxxxxxxxxxxxxxx
Happy orbits !
Andre
xxxxxxxxxxxxxx
No comments:
Post a Comment