1999A&A...346..139H

The anomalous strength of the Fe II λ6147.7 line relative to Fe II λ6149.2 in the stars with magnetic fields is used for detecting magnetic fields in very slowly rotating HgMn stars. The diagnosis based on this pair of magnetically sensitive Fe lines is a simple and fast tool, but its application to more rapidly rotating HgMn stars is hampered by blending with Hg II λ6149.5. For spectra of sharp-lined HgMn stars (with vsini<4km/s) taken at high resolving power (R≥100000) both lines, Fe II λ6149.25 and Hg II λ6149.48, become fully unblended. The observed relative differences between the equivalent widths of the two Fe II lines are compared with those derived from synthetic spectra computed by neglecting magnetic field effects. This comparison has shown that three HgMn stars, HD 175640, HD 178065 and HD 186122 are very likely to possess a magnetic field that could be larger than 2kG.