>Hubble's tuning fork has been more or less the standard for a century now. It's done a decent job, but there have been some galaxies that don't fit the pattern. For example, one might have a small bulge but tight arms, or another with a large bulge and fairly open arms. If there's a galaxy that didn't quite fit, astronomers usually used the arm structure to place it in the diagram.
More specificly, it suggests that there are additional categories that should be added.
The fork used 2 variables to come up with 6 combinations: bulge size( with 3 states) and bar presence (with 2 states). A third variable, arm angle, was assumed to be linked with bulge size.
the data suggests that arm angle does not have the relation to bulge size that was assumed.
More specificly, it suggests that there are additional categories that should be added.
The fork used 2 variables to come up with 6 combinations: bulge size( with 3 states) and bar presence (with 2 states). A third variable, arm angle, was assumed to be linked with bulge size.
the data suggests that arm angle does not have the relation to bulge size that was assumed.