A Study of the Variability of H\(\alpha\) Emission Line Parameters in \(\pi\) Aqr as a Be Star
Taufieq Zannata Ramadhan (a*), Aprilia (b)

Astronomy Study Program, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia

Abstract

B-emission (Be) star is a B type star which shows emission line in its spectrum, especially H\(\alpha\), caused by the disk surrounding it. One of the Be stars, \(\pi\) Aqr, is a binary Be star in constellation Aquarius which shows variability of double peak H\(\alpha\) emission line caused by the disk around the primary component. We aim to study physical phenomenon which occurred in the disk of \(\pi\) Aqr star based on its spectral data from 2004 to 2024, retrieved from Bess database, by analyzing the variability of its H\(\alpha\) emission line parameters: the Violet-to-Red peak ratio (V/R), emission-to-continuum ratio (E/C), Equivalent Width (EW), Full Width at Half Maximum (FWHM), and peak separation. The variation of V/R ratio from 2004 to 2019 shows period of 84.1 days which corresponds with orbital period of the binary system, indicating binary system plays a direct role in the shape of the disk. The EW and E/C increase, indicating rising disk activity until 2024. Peak separation roughly suggests expansion in H\(\alpha\) region in the disk. However, we found that in 2024, the V/R variability shows longer period which disagrees with the previous data. Therefore, we need further spectrum data to confirm this.

Keywords: Be star, \(\pi\) Aqr, Spectrum Variability, Line Parameter

Topic: Earth Physics and Space Science