The relationship between solar activity and the H and K line cores in integrated sunlight

In this paper we present and analyze new data on the cores of the H and K lines of ionized calcium in the spectrum of integrated sunlight. The intensities of the components H _2v , H₃, H _2r , K _2v , K₃, and K _2r in the line cores were measured in terms of the continuum intensity at 4000 Å during a solar rotation in September 1969. Other data on these components, obtained at or close to the times of solar minimum (September 1964) and solar maximum (September 1968), were also included. The intensities of these features are compared with two indices of solar activity: the Ca ii plage index and the 2800 MHZ signal. The average correlation coefficients between the intensities of the measured features and those indices were 0.69 and 0.64, respectively. Our results are consistent with those of Bumba and Riková-Topolová (1967) for a solar rotation period in 1965.The method and results should provide a detailed quantitative basis for the study of the activity cycles and rotation periods of solar-type stars.First Weather Wing, Hickman Air Force Base, HI 96824, U.S.A.