High-dispersion spectrograms for an unbiased sample of 256 late B-type stars are examined in an attempt to determine whether slow rotation is necessary and sufficient for the appearance of HgMn anomalies in nonmagnetic stars. The peculiar stars in the sample are identified, values of v sin i are derived for all the stars observed, and the radial-velocity variations of the identified HgMn stars are analyzed. The distribution of rotational velocities for late B-type stars is obtained, and the role of rotation in producing extended envelopes is evaluated. The binary frequency and mass-ratio distribution are derived for systems containing HgMn components, the effect of duplicity on the distribution of rotational velocities is estimated, and the role of such factors as rotation, age, and binary characteristics in determining whether HgMn anomalies are present is investigated. The results clearly show that HgMn stars occur only within a limited temperature range, that all such stars rotate slowly, but that rotation, effective temperature, age, surface gravity, and binary properties do not serve to determine whether a star will exhibit abundance anomalies.
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Wolff et al. (1978) studied this question.