CAOSP abstracts, Volume: 41, No.: 2, year: 2011

Abstract: We present a quantitative and comparative analysis of sensitivity to the line-of-sight velocity of the spectral line Ba II 6497 Å identified as a very promising Doppler mapper of the solar photosphere and low chromosphere. We examine its sensitivity to changes of the line-of-sight velocity by sharpness of its line profile and the response function to the line-of-sight velocity evaluated by the 1-D model of the quiet solar atmosphere in the LTE approximation. We compare its sensitivity with selected barium, iron, and chromium lines widely used in the diagnostics of the solar photosphere. The set of selected lines includes the Ba II 4554 Å line, generally considered to be an excellent Doppler mapper. The comparison clearly shows that the line Ba II 6497 Å is one of the most sensitive from the lines included in our set. This is due to a favorable combination of a relatively sharp line profile and a long wavelength implying a large Doppler sensitivity. The line Ba II 6497 Å offers many advantages, making it a highly recommendable choice for dedicated studies of line-of-sight velocities in the photosphere and low chromosphere.