First inferences of asteroseismic data of HD122563 from the Hertzsprung telescope
Creevey, O.; Thevenin, F.; Grundahl, F.; Palle, P. L.; Corsaro, E.; Salabert, D.; Bigot, L.; Collet, R.; Antoci, V.; Andersen, M. F.

Abstract

In the era of large galactic and extra galactic surveys it is easy to forget that there are many nearby astrophysical laboratories that can also be used to provide important constraints on our knowledge of the Galaxy, as well as providing crucial insights on astrophysical processes inside stars and their atmospheres. In fact by addressing issues relevant to stellar physics, we can provide much better tools to the community for studying more distant populations.
We present the case of HD 122563, an old metal-poor (Population II) giant at a mere distance of 250 pc. Because it is metal-poor such a star provides an excellent laboratory for constraining models of stellar atmospheres and interiors of old stars. It is also a benchmark star for testing methodologies for interpreting millions of stars from the Gaia mission.
In this talk, we discuss recent observations of this star using many different techniques (e.g interferometry, photometry), and then we present the very first observations of sun-like oscillations in a metal-poor giant star using data from the Hertzsprung telescope of the SONG network. Additionally, new data from the Gaia mission supports our asteroseismic results, but still yields differences of more than a few sigma. prompting much deeper investigations.