The Variability of Halpha Equivalent Widths in Be Stars

TL;DR

This study analyzes the variability of H-alpha equivalent widths in Be stars over four years, introducing a statistical method to quantify their changes and identify different variability stages efficiently.

Contribution

The paper presents a simple F ratio statistical method to quantify Be star variability using observational data, enabling stage identification with minimal data.

Findings

The F ratio effectively quantifies H-alpha variability.

The method can identify Be stars at different variability stages.

Variability bounds can be established with limited observations.

Abstract

Focusing on B-emission stars, we investigated a set of H$\alpha$ equivalent widths calculated from observed spectra acquired over a period of about 4 years from 2003 to 2007. During this time, changes in equivalent width for our program stars were monitored. We have found a simple statistical method to quantify these changes in our observations. This statistical test, commonly called the F ratio, involves calculating the ratio of the external and internal error. We show that the application of this technique can be used to place bounds on the degree of variability of Be stars. This observational tool provides a quantitative way to find Be stars at particular stages of variability requiring relatively little observational data.