~ Polar Ring Galaxy ~
Galaxies
come in various shapes and sizes.
But the Polar Ring seems to be a rather special one..
(extraction
of an article)
The most widely accepted explanation for the formation of polar ring galaxies
is that accreted gas settles
onto orbits that are more frequently contained either within the equatorial
plane or in polar planes.
As Polar Ring Galaxies are typically SO galaxies, and the ring is gaseous,
blue and undergoing star
formation, their nature does not greatly differ from gas-rich SO galaxies,
but the importance of Polar Ring
Galaxies - with respect to the problem of dark matter halos - is that information
about the overall
gravitational potential can be obtained in two planes: the disk and the ring
planes,
thus potentially constraining the shape of the halo.
Don't ask me to explain this...