4. Final comments

Table 8 (click here) compares the abundances of the HgMn stars with those from Adelman (1994) and shows that they fall within the general systematics. To see what correlations of abundance exist, we examined those which are available for all the stars in the table (He I, C II, Si II, Mg II, Si II, S II, Ca II, Ti II, Cr II, Mn II, Fe II, and Y II) with one another and with surface gravity and effective temperature. The correlation is regarded as significant if there is less than one chance in 20 that this value will occur by chance. For 14 items, the absolute value of r must be greater than 0.532 (Bevington & Robinson 1992). Those correlations with absolute r values greater than this are given in Table 9 (click here). However, relative to Adelman's (1992, 1994) similar analyses with smaller number of HgMn stars, only the strongest correlations are found in common. Thus there is no question that the He, Mg, Cr abundances correlate with one another and that the Mn abundance is a function of temperature. The S and Y abundances correlate with one another. But we should cautiously regard the other correlations.

  Table 8:  Comparison of HgMn star abundances (log N/H)

 

He I Ti II 0.567

He I Cr II 0.875

C II Ca II 0.535

Mg II Cr II 0.876

Si II Ti II -0.539

S II Y II 0.686 -0.690 0.650

Cr II Y II 0.548 0.853 0.533

 

These studies showed that the CASLEO spectra have increased the quality of previous analyses. Further the CASLEO equivalent width scale is similar to those for KPNO and DAO spectrograms. Our studies also indicate that for the HgMn stars there are probably a sufficient number of Fe II to determine the microturbulence using the region . Thus elemental abundance analyses of such stars based solely on CASLEO spectrograms in the yellow are anticipated to produce good results.

Acknowledgements

The authors acknowledge use of the CCD and data reduction acquisition system supported by US NSF Grant AST 90-15827 to R.M. Rich. SJA thanks The Citadel Development Foundation for several grants which supported in part this collaboration. OIP is grateful to the staff of CASLEO for their assistance during the observing runs.