The Abundance of Lithium in Sunspots

The absorption line of lithium at 6708 A that is found in sunspots has been observed with a high- resolution interferometric spectrometer, and a theory of line formation applicable to medium-strength lines has been used to interpret the line. if the measured equivalent width of 133 I 3 mA is used, and if a sunspot model suggested by Zwaan is adopted, then the lithium abundance is found to be log [n(Li)/ n(H)j = - 11.32, in general agreement with estimates obtained from observations of the disk spectrum. There may be an uncertainty of up to a factor of 2 in the calculated abundance, depending upon the model chosen for reduction of the data The isotope ratio is n(6Li)/n(7Li) = 0 04 + 0 02. The line-shape parameters, including Zeeman shifts, of twenty-one other lines found in the spot spectrum near 6708 A are also given.