The hot limit of solar-like oscillations from Kepler photometry

TL;DR

This study uses Kepler photometry to identify the hottest stars exhibiting solar-like oscillations, establishing the boundary of convective excitation and its separation from delta Scuti/gamma Doradus regions.

Contribution

It introduces an effective autocorrelation method for detecting low-amplitude solar-like oscillations in hotter stars, expanding the known range of such stars.

Findings

The hot edge of solar-like oscillation excitation does not reach the delta Scuti/gamma Doradus instability strip.

Detected solar-like oscillations in 70 new stars hotter than 6000 K.

Determined $ u_{max}$ and $ riangle u$ for 167 stars, enhancing understanding of stellar oscillation boundaries.

Abstract

Kepler short-cadence photometry of 2347 stars with effective temperatures in the range 6000-10000 K was used to search for the presence of solar-like oscillations. The aim is to establish the location of the hot end of the stochastic convective excitation mechanism and to what extent it may overlap the delta Scuti/gamma Doradus instability region. A simple but effective autocorrelation method is described which is capable of detecting low-amplitude solar-like oscillations, but with significant risk of a false detection. The location of the frequency of maximum oscillation power, $\nu_{\rm max}$, and the large frequency separation, $\Delta\nu$, is determined for 167 stars hotter than 6000 K, of which 70 are new detections. Results indicate that the hot edge of excitation of solar-like oscillations does not appear to extend into the delta Scuti/gamma Doradus instability strip.