HST/STIS high resolution echelle spectra of Centauri A (G2 V) ?;??

We describe and analyze HST/STIS observations of the G2 V star α Centauri A ( α Cen A, HD 128620), a star similar to the Sun. The high resolution echelle spectra obtained with the E140H and E230H gratings cover the complete spectral range 1133-3150 A with a resolution of 2.6 km s -1 , an absolute flux calibration accurate to $\pm 5$%, and an absolute wavelength accuracy of 0.6–1.3 km s -1 . We present here a study of the E140H spectrum covering the 1140–1670 A spectral range, which includes 671 emission lines representing 37 different ions and the molecules CO and H 2 . For α Cen A and the quiet and active Sun, we intercompare the redshifts, nonthermal line widths, and parameters of two Gaussian representations of transition region lines (e.g., $\ion{Si}{iv}$, $\ion{C}{iv}$), infer the electron density from the $\ion{O}{iv}$ intersystem lines, and compare their differential emission measure distributions. One purpose of this study is to compare the α Cen A and solar UV spectra to determine how the atmosphere and heating processes in α Cen A differ from the Sun as a result of the small differences in gravity, age, and chemical composition of the two stars. A second purpose is to provide an excellent high resolution UV spectrum of a solar-like star that can serve as a proxy for the Sun observed as a point source when comparing other stars to the Sun.