Investigation of the negative K effect using the Orion Spiral Arm Catalogue

We created and are constantly updating the Orion Spiral Arm Catalogue for stars with known coordinates, parallaxes, proper motions and radial velocities. It is shown that there is an effect of contraction appearing in the motion of giants of A0–A5 spectral classes which attains a value of K=−13±2 km s−1 kpc−1. We try to link this effect to the periodic structure of the residual velocity field of stars in the solar neighbourhood, which is caused by spiral density waves.