Non-radial Pulsations in the Open Cluster NGC 3766

TL;DR

This study investigates non-radial pulsations in Be and B stars within NGC 3766 using photometry, aiming to understand their role in disk formation and internal stellar structure.

Contribution

It demonstrates the use of multi-color photometry from small telescopes to detect NRPs in stars of NGC 3766, providing a more accessible method for such studies.

Findings

Light curves of Be and B stars show evidence of NRPs.

Photometry can measure pulsation degree l without large telescopes.

NGC 3766's high fraction of transient Be stars makes it ideal for NRP studies.

Abstract

Non-radial pulsations (NRPs) are a proposed mechanism for the formation of decretion disks around Be stars and are important tools to study the internal structure of stars. NGC 3766 has an unusually large fraction of transient Be stars, so it is an excellent location to study the formation mechanism of Be star disks. High resolution spectroscopy can reveal line profile variations from NRPs, allowing measurements of both the degree, l, and azimuthal order, m. However, spectroscopic studies require large amounts of time with large telescopes to achieve the necessary high S/N and time domain coverage. On the other hand, multi-color photometry can be performed more easily with small telescopes to measure l only. Here, we present representative light curves of Be stars and non-emitting B stars in NGC 3766 from the CTIO 0.9m telescope in an effort to study NRPs in this cluster.