Deciphering the period spacing pattern in the oscillation spectrum of the SPB star KIC 7760680

TL;DR

This study analyzes the oscillation spectrum of the SPB star KIC 7760680, revealing a series of quasi-equally spaced frequencies associated with prograde dipole modes, and highlights the importance of opacity modifications in pulsation modeling.

Contribution

The paper provides the first detailed analysis of the period spacing pattern in KIC 7760680, incorporating rotation effects and testing opacity enhancements to match observations.

Findings

The frequency series corresponds to prograde dipole modes of consecutive radial orders.

Enhanced opacities at specific temperatures improve mode excitation in models.

Rotation effects are crucial for accurately modeling the star's pulsation spectrum.

Abstract

We present the analysis of KIC 7760680, the rotating Slowly Pulsating B-type star identified in the Kepler photometry. The oscillation spectrum of the star exhibits a series of 36 frequencies which are quasi-equally spaced in period. We confirm that this series can be associated with prograde dipole modes of consecutive radial orders. In our studies, the effects of rotation were included in the MESA equilibrium models as well as in the puslational calculations in the framework of the traditional approximation. We find that pulsational models computed with the OPLIB opacities best reproduce the observed frequency range. The modified opacity data with an enhancement of the opacity at $\log T=5.3$, 5.46 and 5.06 were tested as well. Increasing the OPLIB opacities by about 50% at $\log T=5.3$ is sufficient to excite modes in the whole range of 36 frequency peaks of KIC 7760680.