FTS atlas of the Sun's spectrally resolved center-to-limb variation

摘要

The Sun's spectrum varies with center-to-limb distance, which is usually parameterized by mu = cos theta, where theta is the heliocentric angle. This variation is governed by the underlying temperature-density structure of the solar atmosphere. While the center-to-limb variation (CLV) of the continuous spectrum is well known and has been widely used for atmospheric modeling, there has been no systematic exploration of the spectrally resolved CLV. Here we make use of two spectral atlases recorded with the Fourier transform spectrometer (FTS) at the McMath-Pierce facility at Kitt Peak.