A Study of 35 Herbig Ae/Be Objects in the UV, with Support from Optical and IR Datasets
Session 17 -- Stellar Spectroscopy and Photometry: Surveys and General results
Display presentation, Wednesday, January 12, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [17.04] A Study of 35 Herbig Ae/Be Objects in the UV, with Support from Optical and IR Datasets

J.M.S. Silvis (Catholic U.), F. Bruhweiler (Catholic U.)

We have examined the IUE archival data for 35 Herbig Ae/Be stars and found that the UV characteristics of the stars break into two distinct groups. The UV broad-line stars have extremely wide absorption features from lines arising from metastable Fe II and Fe III. They also have Ly-$\alpha$ emission. The UV narrow-line stars have little or no Fe II and Fe III absorption and have strong absorption features of highly ionized C~IV and Si~IV. These highly ionized species cannot be produced by the radiation field of the star, and likely arise in spiral shocks or a chromosphere-like boundary layer. Comparison with IR data implies that the UV broad-line stars are less evolved than the UV narrow-line stars. Thus the difference between these groups suggest an evolutionary sequence. We have correlated accretion rates with the inferred mass outflow, and searched for continuum variations over a range of timescales. Also we have compared the mass accretion rate between the two groups. Possible physical models are presented to explain these observations.