Kepler observations of a roAp star: delta Scuti and gamma Doradus pulsations in Ap stars

TL;DR

This paper reports Kepler observations revealing multiple pulsation types, including for the first time gamma Doradus and delta Scuti pulsations, in Ap stars, challenging existing models of stellar oscillations.

Contribution

It presents the first detection of gamma Doradus and delta Scuti pulsations in Ap stars, expanding understanding of stellar pulsation phenomena.

Findings

Detection of several frequencies near 10 min in a roAp star

Identification of low-frequency gamma Doradus pulsations in Ap stars

Simultaneous presence of roAp, gamma Doradus, and delta Scuti pulsations

Abstract

Observations of the A5p star KIC 8677585 obtained during the Kepler 10-d commissioning run with 1-min time resolution show that it is a roAp star with several frequencies with periods near 10 min. In addition, a low frequency at 3.142 cycles/day is also clearly present. Multiperiodic gamma Doradus and delta Scuti pulsations, never before seen in any Ap star, are present in Kepler observations of at least three other Ap stars. Since gamma Doradus pulsations are seen in Ap stars, it is likely that the low-frequency in KIC 8677585 is also a gamma Doradus pulsation. The simultaneous presence of both gamma Doradus and roAp pulsations and the unexpected detection of delta Scuti and gamma Doradus pulsations in Ap stars present new opportunities and challenges for the interpretation of these stars.