# First Results From The Hertzsprung Song Telescope: Asteroseismology Of The G5 Subgiant Star {\Mu}Her

## TL;DR

This paper presents initial asteroseismic findings from the Hertzsprung SONG Telescope on the G5 subgiant star {}Her, revealing detailed stellar oscillation modes, rotation, and internal structure parameters.

## Contribution

First high-precision asteroseismic analysis of {}Her using the SONG Telescope, providing detailed stellar oscillation data and internal structure insights.

## Key findings

- Detected 49 oscillation modes including mixed modes
- Determined stellar rotation period of 52 days
- Estimated stellar mass between 1.11 and 1.15 solar masses

## Abstract

We report the first asteroseismic results obtained with the Hertzsprung SONG Telescope from an extensive high-precision radial-velocity observing campaign of the subgiant muHerculis. The data set was collected during 215 nights in 2014 and 2015. We detected a total of 49 oscillation modes with l values from 0 to 3, including some l = 1 mixed modes. Based on the rotational splitting observed in l = 1 modes, we determine a rotational period of 52 days and a stellar inclination angle of 63 degrees. The parameters obtained through modeling of the observed oscillation frequencies agree very well with independent observations and imply a stellar mass between 1.11 and 1.15M_sun and an age of 7.8+/-0.4 Gyr. Furthermore, the high-quality data allowed us to determine the acoustic depths of the He II ionization layer and the base of the convection zone.