Scaled oscillation frequencies and echelle diagrams as a tool for comparative asteroseismology

TL;DR

This paper introduces a method using scaled echelle diagrams for direct comparison of stellar oscillation spectra, enabling precise density ratio estimation and improved mode identification without relying on theoretical models.

Contribution

The authors present a novel approach to compare oscillation spectra of stars through scaled echelle diagrams, facilitating model-independent analysis and resolving ridge identification issues.

Findings

Allows precise ratio of mean stellar densities without models

Enhances confirmation of weak modes using better signal-to-noise data

Provides a solution for ridge identification in F-type stars

Abstract

We describe a method for comparing the frequency spectra of oscillating stars. We focus on solar-like oscillations, in which mode frequencies generally follow a regular pattern. On the basis that oscillation frequencies of similar stars scale homologously, we show how to display two stars on a single echelle diagram. The result can be used to infer the ratio of their mean densities very precisely, without reference to theoretical models. In addition, data from the star with the better signal-to-noise ratio can be used to confirm weaker modes and reject sidelobes in data from the second star. Finally, we show that scaled echelle diagrams provide a solution to the problem of ridge identification in F-type stars, such as those observed by the CoRoT space mission.