Empirical investigation on the impact of hydrogen collisions for the formation of CI 1.07μm lines based on the solar center-to-limb variation?

摘要

With the aim of examining the validity of non-LTE line-formation calculations for the strong C I lines of multiplet 1 at 1.068–1.069μm, especially in terms of the treatment of collisions with neutral hydrogen (HI) atoms, we computed theoretical equivalent widths (W_λ) of these lines corresponding to specific intensities of different angles (μ = cos θ) on the solar disk under various conditions, which were then compared with the empirical W_λ vs. μ relations obtained from our spectroscopic observations with the Domeless Solar Telescope at Hida Observatory. It turned out that our observational data are almost consistent with the theoretical simulations done with the HI collision rates computed with the classical formula, which suggests that the necessity of its significant revision (e.g., considerable reduction) is unlikely.