Tidal Interaction in High Mass X-ray Binaries

TL;DR

This study examines tidal interactions in High-Mass X-ray Binaries to determine synchronization states, revealing that Be/X-ray binaries are generally not synchronized while giant and supergiant systems tend to be closer to synchronization.

Contribution

It provides the first detailed comparison of pseudosynchronization and rotational periods across different types of High-Mass X-ray Binaries.

Findings

Be/X-ray binaries are not synchronized, with donors rotating faster than orbital periods.

Giant and supergiant systems are close to synchronization.

The ratio P_ps/P_rot varies from 0.3 to 300 across systems.

Abstract

Our aim is to investigate tidal interaction in High-Mass X-ray Binary stars in order to determine in which objects the rotation of the mass donors is synchronized or pseudosynchronized with the orbital motion of the compact companion. We calculate the pseudosynchronization period (P_ps) and compare it with the rotational period of the mass donors (P_rot). We find that (1) the Be/X-ray binaries are not synchronized, the mass donors rotate faster than the orbital period and the ratio P_ps/P_rot is 2-300; (2) the giant and supergiant systems are close to synchronization and for them the ratio P_ps/P_rot is 0.3-2.