Monitoring the Solar Temperature: Empirical Calibration of the Temperature Sensitivity of Ciλ5380

Abstract
We observed a set of six dwarf stars spanning a range in temperatures around the solar value, and from them we have determined empirically the temperature sensitivity of C I λ5380.32, a line that has been monitored in the solar flux spectrum for nearly two decades at Kitt Peak. When the C I line is compared to the adjacent Fe I λ5379.58 line, it should be possible to detect apparent temperature differences of a fraction of 1 K.