the $\delta$-Sct stars (dot-dashed line in Fig.8) [@lia] and to those all radially pulsating variable stars (dashed line) [@fer]. While the slope is about -3.3 for the $\delta$-Sct stars, -0.88 for the radially pulsating variable stars. The pulsation periods of $\gamma$-Dor type pulsators seem to depend on the surface gravity similar to those radially pulsating variable stars proposed by [@fer].

The gravitational force applied to per gram matter on the surface of the pulsating component can be determined by

$$g =  G \times \frac{M_{puls}} {R_{puls}^2}.$$

Since P$_{puls}$ depends on the R$_{puls}$ and M$_{puls}$ as given in Eq.4 we can easily obtain,

$$P_{puls} = Q \times G^{\frac{1}{2}} \times R_{puls}^{ \frac{1}{2}} \times g^{-\frac{1}{2}}$$

The pulsational period is inversely proportional of the square root of the surface gravity of the pulsating star.

We also plot in Fig.9 the pulsational periods of the oscillating primary components against the gravitational pull exerted to the per gram of the matter on the surface of the pulsators by the less massive companions (in cgs units). The short orbital period binary VZ CVn appears to have longer pulsational period with respect to the gravitational pull of the companion. This star is significantly separated from the other stars. It 