Asteroseismic fingerprints of rotation and mixing in the slowly pulsating B8 V star KIC 7760680

TL;DR

This study analyzes four years of Kepler photometry and high-resolution spectra of the B8 V star KIC 7760680, revealing a series of gravity modes affected by rotation and mixing, providing key insights for stellar modeling.

Contribution

It presents the first detection of a long series of gravity modes in a SPB star, offering detailed seismic constraints for stellar structure models.

Findings

Detection of 36 consecutive high-order sectoral dipole gravity modes

Signatures of chemical mixing and rotation in the mode series

KIC 7760680 is near the cool edge of the SPB instability strip

Abstract

We present the first detection of a rotationally affected series consisting of 36 consecutive high-order sectoral dipole gravity modes in a slowly pulsating B (SPB) star. The results are based on the analysis of four years of virtually uninterrupted photometric data assembled with the Kepler Mission, and high-resolution spectra acquired using the HERMES spectrograph at the 1.2 meter Mercator Telescope. The spectroscopic measurements place KIC7760680 inside the SPB instability strip, near the cool edge. The photometric analysis reveals the longest unambiguous series of gravity modes of the same degree l with consecutive radial order n, that carries clear signatures of chemical mixing and rotation. With such exceptional observational constraints, this star should be considered as the Rosetta Stone of SPBs for future modelling, and bring us a step closer to the much needed seismic calibration of stellar structure models of massive stars.