The Discovery of Stellar Oscillations in the Planet Hosting Giant Star Beta Geminorum

TL;DR

This study reports the detection of solar-like oscillations in the planet-hosting giant star Beta Geminorum, revealing multiple pulsation modes that can improve stellar mass estimates.

Contribution

First detection of multi-periodic stellar oscillations in a planet-hosting giant star, providing new insights into stellar properties and exoplanet characterization.

Findings

Detected six significant pulsation modes

Oscillation frequencies range from 30 to 150 microHz

Dominant mode at 86.9 microHz with 5.3 m/s amplitude

Abstract

We present the results of a long time series of precise stellar radial velocity measurements of the planet hosting K giant star Beta Geminorum. A total of 20 hours of observations spanning three nights were obtained and the radial velocity variations show the presence of solar-like stellar oscillations. Our period analysis yields six significant pulsation modes that have frequencies in the range of 30 - 150 microHz. The dominant mode is at a frequency of 86.9 microHz and has an amplitude of 5.3 m/s. These values are consistent with stellar oscillations for a giant star with a stellar mass of approximately 2 solar masses. This stellar mass implies a companion minimum mass of 2.6 Jupiter masses. Beta Gem is the first planet hosting giant star in which multi-periodic stellar oscillations have been detected. The study of stellar oscillations in planet hosting giant stars may provide an independent, and more accurate determination of the stellar mass.