THE LITHIUM ABUNDANCE IN SUNSPOTS

The solar lithium abundance was determined using an empirical model fo r an observed sunspot umbra. The atmospheric model is deduced from a n umber of spectral lines. In addition to the lithium (I) line doublets from Li-6 and Li-7 at 670.8 nm eight different line profiles were obse rved with high spectro-graphic resolution. A magnetically sensitive li ne was included in order to determine the magnetic field strength. An estimation for the influence of molecular blends caused by CN and TiO was taken into account. Under the assumption of LTE a lithium abundanc e of epsilon(Li) = 1.02 +/- 0.12(1) was derived. Some evidence for the existence of a small but notable amount of Li-6 is found, however onl y an upper limit of Li-6/Li-7 less than or equal to 0.03 can be derive d. A more precise determination of the isotopic ratio is hampered by t he uncertainties induced by the presence of TiO blends.