Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Binary stars



I am not aware that the terminology is as set in stone as Leigh suggests.
Which means things can be more confusing then they should be. He is right,
of course, that the symmetry of a geometric infinite cylinder and a
geometric circle are different; one involving an ignorable z-coordinate.
I'd suggest that all readers beware, as often references to cylindrical
symmetry don't necessarily mean ignorable z-coordinate. Which makes me
agree that terminology is important.

BTW Leigh, How do you distinguish with your terminology the difference
between an infinite cylinder and a finite length cylinder?

I might add for folks' information; that one often sees the term "axial
symmetry", which I believe to be the as the "azimuthal symmetry" to which
Leigh refers.

Joel Rauber
Joel_Rauber@sdstate.edu


I think circular and cylindrical symmetry are different animals.
Cylindrical symmetry entails also an ignorable *z-coordinate*. There
are quantum mechanical *solutions* to cylindrically symmetrical
physical systems which do have circular symmetry except only in the
sense that the phase of the wave function in the azimuthal direction
is arbitrary unless it is split by some externally applied term. m=0
corresponds to circular symmetry. Circular symmetry is a subgroup of
cylindrical symmetry. I is also called "azimuthal symmetry".

I think the terminology is important.

Leigh