Data from paper

Investigating the atmospheric composition of cool, evolved stars is an important step to furthering our understanding of stellar life cycles, galaxy formation, and the origination of material that forms exoplanets. In this context, we analyze the far-ultraviolet (FUV) spectra produced by the chromosphere of the K-giant star $\beta$ Ceti using high-quality far-ultraviolet spectral data collected by the Hubble Space Telescope Space (HST) Telescope Imaging Spectrograph (STIS). We first measure the surface fluxes of a set of single emission line profiles, and then self-reversed lines, by fitting one or more Gaussian curves to these lines. We then identify significant atomic features in the spectra, and derive the full-width at half-maximum, radial velocity, and other parameters measuring the strength and intensity of each line. We also determine the opacity of the lines to better understand the inflow and outflow of material. We have measured a collection of strong lines in the transition metals group, detected emissions indicative of hot plasma up to temperatures of 200,000 K, and identified a number of self-reversed lines to provide empirical measurements of the wind acceleration surrounding the star. These reference spectra will support necessary future comprehensive studies of cool, evolved stars in the Galaxy and beyond.