Magnetic, Basal, and Radiative-Equilibrium Components in Mount Wilson Ca II H + K Fluxes

摘要

Mount Wilson Ca II H + K flux measurements of cool dwarf stars are analyzed comparing the fluxes with stellar Mg u h + k fluxes, variability amplitudes, rotation rates, and solar data. We conclude that the Mount Wilson Ca U H + K fluxes comprise three principal parts: (1) a photospheric contribution in the line wings, (2) a basal chromospheric component that appears to be unrelated to stellar magnetic activity and is therefore possibly nonmagnetic in origin, and (3) a chromospheric component which we associate with magnetically active regions and the (quiet and active) network. The basal chromosphere appears to cover the entire surface of magnetically inactive stars. The basal Ca II H + K flux density for solar-type stars equals the average emission observed in the center of solar supergranulation cells, where the magnetic flux density is small. Keywords: Solar activity; Stellar Activity; Solar Atmospheres; Reprints. (JHD)