Spectral Analysis and Classification of Herbig Ae/Be Stars

We present an analysis of the optical spectra of 75 early-type emission-line stars, many of which have been classified previously as Herbig Ae/Be (HAeBe) stars. Accurate spectral types were derived for 58 members of the sample; high continuum veiling, contamination by nonphotospheric absorption features, or a composite binary spectrum prevented accurate spectral typing for the rest. Approximately half of our sample exhibited [O I] λ6300 forbidden-line emission down to our detection limit of 0.1 Å equivalent width; a third of the sample exhibited Fe II emission (multiplet 42). A subset of 11 of the HAeBe sample showed abnormally strong Fe II absorption; 75% of this subset are confirmed UX Ori objects. Combining our spectral typing results with photometry from the literature, we confirm previous findings of high values of total-to-selective extinction (RV ∼ 5) in our larger sample, suggesting significant grain growth in the environments of HAeBe stars. With this high value of RV, the vast majority of HAeBe stars appear younger than with the standard RV = 3.1 extinction law and are more consistent with being pre–main-sequence objects.

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