Observations of intensity fluctuations attributed to granulation and faculae on Sun-like stars from the Kepler mission

TL;DR

This study analyzes Kepler data of Sun-like stars to identify and compare intensity fluctuation signatures from granulation, faculae, and oscillations, revealing periodic variability similar to the Sun.

Contribution

It provides the first detailed analysis of faculae signatures in Sun-like stars using Kepler data, highlighting their variability and similarities to solar phenomena.

Findings

Signatures of granulation, faculae, and p-mode oscillations are present in all three stars.

Granulation and faculae show periodic variability similar to the Sun.

Faculae signatures are convincingly detected in stellar frequency spectra.

Abstract

Sun-like stars show intensity fluctuations on a number of time scales due to various physical phenomena on their surfaces. These phenomena can convincingly be studied in the frequency spectra of these stars - while the strongest signatures usually originate from spots, granulation and p-mode oscillations, it has also been suggested that the frequency spectrum of the Sun contains a signature of faculae. We have analyzed three stars observed for 13 months in short cadence (58.84 seconds sampling) by the Kepler mission. The frequency spectra of all three stars, as for the Sun, contain signatures that we can attribute to granulation, faculae, and p-mode oscillations. The temporal variability of the signatures attributed to granulation, faculae and p-mode oscillations were analyzed and the analysis indicates a periodic variability in the granulation and faculae signatures - comparable to what is seen in the Sun.