Let there be more variability in two gamma Cas stars [SSA]

http://arxiv.org/abs/2002.12656


We investigate the short-term optical variability of two gamma Cas analogs, pi Aqr and BZ Cru, thanks to intensive ground-based spectroscopic and space-borne photometric monitorings. For both stars, low-amplitude (mmag) coherent photometric variability is detected. The associated signals display long-term amplitude variations, as in other Be stars. However, these signals appear at high frequencies, especially in pi Aqr, indicating p-modes with a high degree l, a quite unusual feature amongst Be stars. While BZ Cru presents only low-level spectral variability, without clear periodicity, this is not the case of pi Aqr. In this star, the dominant photometric frequencies, near ~12/d, are confirmed spectroscopically in separate monitorings taken during very different disk activity levels ; the spectroscopic analysis suggests a probable tesseral nature for the mode.

Read this paper on arXiv…

Y. Naze, A. Pigulski, G. Rauw, et. al.
Mon, 2 Mar 20
54/62

Comments: accepted by MNRAS – the arxiv version has some figures in low-resolution