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eburacum45
2018-Dec-08, 01:50 PM
I've always avoided the use of stellar rosettes in Orion's Arm, even though they have appeared in fiction elsewhere (in Arthur Clarke's novel The City and The Stars, and (briefly) in Futurama). By a stellar rosette I mean a ring or regular polygon of stars, with or without a central star. I have always assumed that the stellar rosette without a central star is not stable, and the rosette with a central star is just as stable as any other Klemperer rosette. But I'd love to be proved wrong.

In short; is a ring of stars with no central stellar object unstable, or would it be possible to make a stable or quasi-stable ring?

Noclevername
2018-Dec-08, 01:58 PM
Unstable. Any eruption is a jet.

grant hutchison
2018-Dec-08, 02:01 PM
They are all unstable, irrespective of whether there's a star in the middle or not, as Klemperer pointed out in his original paper (http://adsabs.harvard.edu/abs/1962AJ.....67..162K). The reason is that any small perturbation destroys the symmetry, after which gravity increases the symmetry breaking.

As a side note (I'm sure eburacum45 knows this bit of history) the things that are now called "Klemperer rosettes" are not the things discussed by Klemperer - his discussion concerned much more interesting arrays with elliptical orbits and carefully tuned masses. He felt the circular equal-mass case was "trivial". Larry Niven is to blame for trivializing poor Klemperer (and spelling his name wrongly).

Grant Hutchison

grant hutchison
2018-Dec-08, 02:02 PM
Any eruption is a jet.That seems gnomic. What do you mean?

Grant Hutchison

eburacum45
2018-Dec-08, 03:53 PM
I think he means that a coronal mass ejection or stellar eruption of any kind would act as a rocket, so disturb the stability. Perhaps a sufficiently advanced civilisation could use this effect to maintain stationkeeping, but the problems associated with this kind of rocketry are very significant.