# How do Oort's constants relate to shear and vorticity?

I am told to show that Oort's constants represent shear and vorticity in the velocity field of an orbiting star. I know that Oort's constants are defined as:

$$A = \frac{1}{2}(\frac{v_{\bot,0}}{R_{0}}-\frac{dv_{\bot}}{dR})$$

$$B = -\frac{1}{2}(\frac{v_{\bot,0}}{R_{0}}+\frac{dv_{\bot}}{dR})$$

and are evaluated at $$R_{0}$$. I also know that shear roughly describes how the circular orbit is stretched and vorticity describes something like the circular motion relative to a given point that itself is in a circular orbit.

How can these equations be related to these concepts?