Non-radial pulsations in the Be/X binaries 4U0115+63 and SAXJ2103.5+4545

TL;DR

This study investigates non-radial pulsations in two Galactic Be/X-ray binaries, comparing their short-term variability to similar systems in the Magellanic Clouds and isolated Be stars, revealing multiperiodicity and periodicity.

Contribution

First detailed analysis of non-radial pulsations in Galactic Be/X-ray binaries, expanding understanding of stellar pulsations in these systems.

Findings

4U0115+63 shows multiperiodicity.

SAXJ2103.5+4545 exhibits periodicity.

Results suggest non-radial pulsations influence variability.

Abstract

The discovery of non-radial pulsations (NRP) in the Be/X binaries of the Magellanic Clouds (MC, eg. Fabrycky 2005, Coe et al. 2005, Schmidtke & Cowley 2005) provided a new approach to understand these complex systems, and, at the same time, favoured the synergy between two different fields: stellar pulsations and X-ray binaries. This breakthrough was possible thanks to the MACHO and OGLE surveys. However, in our Galaxy, only two Be/X have been reported to show NRP: GROJ2058+42 (Kiziloglu et al. 2007) and LSI+61 235 (Sarty et al. 2009). Our objective is to study the short-term variability of Galactic Be/X binaries, compare them to the Be/X of the MC and to the isolated Galactic Be observed with CoRoT and Kepler. We present preliminary results of two Be/X stars, namely 4U0115+63 and SAXJ2103.5+4545 showing multiperiodicity and periodicity respectively, most probably produced by non-radial pulsations.