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Hubble finds something peculiar: planet-forming theories challenged

By Paul Wallis     Jul 22, 2007 in Science
A new star isn’t doing what it’s supposed to be doing. The normal dusty debris around it is in a highly elliptical, lopsided, orbit. OK, a young star’s gotta have some fun, but this one’s writing its own rules.
The conventional theory is that planets are affecting the disk. In our Solar System, one theory is that the gravitational forces of planets shuffled our planets so that Neptune which originally formed between Saturn and Uranus, was pushed out of that orbit. In some cases this gravitational whiplash is believed capable of throwing planets out into interstellar space, away from their home systems.
At this stage it’s believed that when a planet’s orbit becomes elliptical through a “violent upheaval” in its system it affects the disk. Another possibility is that a nearby star is affecting the disk, although this is just a theory, in this case.
Not that the original set of theories astronomy started with is standing up too well to what we’re seeing in exoplanets. Gas giants closer to their sun that Mercury with orbits around a star of nine hours weren’t on the travel brochure, either. Nor were the superplanets.
My guess would be that such an extremely elliptical disk would have to be formed by some high energy force behaving differently to a classic distribution and rotation pattern. Planets in our solar system have relatively mild elliptical patterns. In magnetic fields, ellipses tend to relate to the inner field, and are much more intense than the broader outer field shapes. It may be that the disk has conformed to that part of the field because of its content, containing elements more susceptible to high energy fields.
A planet’s movement by gravitational fluxes may well have swept the dust into that shape, (it is undeniably an orbital shape, if a pretty weird one) but what happens next? Will the disk behave itself and form planets, or will we have a ringed star with a high energy dust cloud around it?
One thing about astronomy, it never gets dull, and it’s got quite a repertoire of subject matter.
More about Hubble, Accretion disk, Gravity