The solar abundance of silver

Abstract

Low noise, high resolution spectral scans have been obtained for the resonance lines of silver λ3280.7 and λ3382.9, observed at the centre of the solar disk. A double pass-monochromator is used in conjunction with the Snow telescope at Mount Wilson; the transparency of the sky is monitored during the observations in order to achieve required accuracy. The data are analyzed by the method of spectral synthesis wherein we employ a model atmosphere resembling Elste's (1968) model and checked by limb-darkening observations. The present kinematical model adopts a macroturbulent velocity of 2.2 km s−1 and no microturbulence. With this model line profiles can be reproduced without invoking implausibly large collisional damping constants. The silver abundance turns out to be {Ag}=log[N(Ag)/N(H)]+12;=0.85, a factor of four under the value found from the Type I carbonaceous chondrites.