Solar-like oscillations in alpha Centauri B

TL;DR

This study detects and analyzes solar-like oscillations in alpha Centauri B, identifying multiple modes and comparing their properties to the Sun, while also introducing a new amplitude measurement method applicable to various stars.

Contribution

It presents the first detailed mode identification in alpha Cen B and introduces a novel technique for measuring oscillation amplitudes from smoothed power spectra.

Findings

37 oscillation modes identified in alpha Cen B

Mode lifetime similar to the Sun

New amplitude measurement method introduced

Abstract

We have made velocity observations of the star alpha Cen B from two sites, allowing us to identify 37 oscillation modes with l=0-3. Fitting to these modes gives the large and small frequency separations as a function of frequency. The mode lifetime, as measured from the scatter of the oscillation frequencies about a smooth trend, is similar to that in the Sun. Limited observations of the star delta Pav show oscillations centred at 2.3 mHz with peak amplitudes close to solar. We introduce a new method of measuring oscillation amplitudes from heavily-smoothed power density spectra, from which we estimated amplitudes for alpha Cen A and B, beta Hyi, delta Pav and the Sun. We point out that the oscillation amplitudes may depend on which spectral lines are used for the velocity measurements.