Judging from the elements present in the star, we conclude that the underlying star has the characteristics of a late O or early B type as far as He II, O III, Si III and S III are concerned. The other elements present correspond to the shell a nd judging from the elements present in the shell spectrum, correspond to a spectral type of at most an A type object. The combination of a hot underlying photosphere and a much cooler extended atmosphere is in fact characteristic of the stars investigated so far in this series of papers.
If we compare to other stars of the group, the star is similar to OY Gem(=HD 51585), MWC 349 and MWC 645 as far as no absorption lines are seen. With respect to elements found, the best analog is OY Gem, although the two other stars are also similar. We find the following elements in common: H, He, C, N, O, Mg, Si, S, Ti, Cr, Fe and Ni.
AcknowledgementsWe thank Mr. Ph. Moreau from the Haute Provence Observatory for the reproductions of the spectra of Fig. 1.
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