A New Look into K-giants' Chromospheres

We report the preliminary modeling of archival Center for High Angular Resolution Astronomy (CHARA)/Visible spEctroGraph and polArimeter interferometric data of a K-giant star using the PHOENIX atmosphere code. We find that our preparatory model that includes only the chromospheric contribution closely reproduces the observed infrared Ca II triplet line profiles of a test star: the K-giant, β Cet. This preliminary work requires the additional modeling of the wind contribution to improve the agreement with observations. We plan to perform a systematic study of K-giants chromospheric emission with multi-wavelength and multi-technique observations and modeling. Our plans include extending the modeling work to include the underlying wind component for a larger set of stars. Stellar Parameters and Images with a Cophased Array, the second-generation instrument at CHARA, will be the ideal instrument to perform such observations and reveal the chromospheric activity of K-giants.