A Study of the Middle-Aged Sun: beta Comae

We propose to obtain highquality spectra of the middleaged (1.6 Gyr) solaranalog beta Comae. This observation will conclude a comprehensive Xrayspectroscopic study of the XRay Sun in Time with XMMNewton, obtaining datafrom a star at the critical transition between magnetically active, rapidlyrotating young stars and stars like the Sun. One of the main goals of this studyis a deeper understanding of the coronal composition of solar analogs atdifferent ages. For younger solar analogs, we find a systematic trend fromunderabundant elements with low first ionization potentials in very active starsto overabundances of the same elements in less active stars. Our target willallow us to extend this study to the complete mainsequence evolution of a solartype star. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]