Observations of the Bowen Fluorescent Mechanism in Planetary Nebulae

Abstract

Measurements of Bowen fluoresecent lines in 17 planetary nebulae are presented and the relative line strength is composed with theory. There is generally good agreement with the line intensities expected by Saraph and Seaton (1980). The largest deviation from theory is in the O III I(3429A/I3444A) ratio, which is consistently lower than predicted. Certain lines are enhanced by charge transfer, and the predicted contribution has been calculated. The results reported here support the charge transfer rate published in 1982 by Dalgarno and Sternberg. The Bowen efficiency is calculated for each of the planetary nebulae considered; the range of values indicates differences between the nebulae. Bipolar and double-ringed planetaries whose central stars display continuous spectra are found to have the lowest efficiencies.