I've read that LIGO will be the first thing to detect a "nearby" core collapse supernova, because the neutrino pulse travels slower than light, and the light is trapped inside the star for several hours before it is free to propagate in a vacuum.
However, can a core collapse supernova emit detectable gravitational waves? I'm not up to tackling the GR equations involved, but ...
If it's spherically symmetrical, then it has no preferred direction. A gravitational wave stretches space in one direction while compressing it in the perpendicular one. So emission of such is not compatible with perfect spherical source symmetry. Am I right?
A star is rotating, which gives it a defined axis. Does that make a difference? It still doesn't seem able to define any perpendicular "stretch" and "shrink" directions, if it has perfect radial symmetry. Again, am I right?
If I'm not wrong, this leaves the fact that no real star collapse will actually be perfectly symmetrical. If so, are the expected deviations from radial symmetry during the collapse sufficient to make a core collapse supernova detectable by LIGO, and at what estimated distance? Does it make any difference whether the core ends up as a neutron star or a black hole?