A photometric study of Be stars located in the seismology fields of COROT

TL;DR

This study analyzes photometric data of 84 Be stars in COROT's seismology fields, identifying pulsational properties and variability patterns to understand the Be phenomenon's origins.

Contribution

It provides the first detailed characterization of short-term pulsations in Be stars using combined ground-based and space-based photometry.

Findings

74% of early-type Be stars show short-term variability

Non-radial pulsations are more frequent in Be stars than in slow-rotating B stars

Identified 7 multiperiodic and 21 monoperiodic variable Be stars

Abstract

Context: In preparation for the COROT mission, an exhaustive photometric study of Be stars located in the seismology fields of the COROT mission has been performed. The very precise and long-time-spanned photometric observations gathered by the COROT satellite will give important clues of the origin of the Be phenomenon. Aims: The aim of this work is to find short-period variable Be stars located in the seismology fields of COROT and to study and characterise their pulsational properties. Methods: Light curves obtained at the Observatorio de Sierra Nevada together with data from Hipparcos and ASAS-3 of a total of 84 Be stars have been analysed in order to search for short-term variations. We have applied standard Fourier techniques and non-linear least-square fitting to the time series. Results: We have found 7 multiperiodic, 21 mono-periodic and 26 non-variable Be stars. Short-term variability has been detected in 74% of early-type Be stars and in 31% of mid- to late-type Be stars. We have shown that non-radial pulsations are most frequent among Be stars than in slow-rotating B stars of the same spectral range.