The variable Herbig AE star HR 5999. IX. Variability in the UV shell lines.

Abstract

The young Herbig Ae star HR 5999 has been observed with the IUE in high resolution for six different phases of brightness. The equivalent width and half-width of a set of low excitation lines are measured. Both quantities appear to be correlated with the variation of the stellar magnitude in the sense that they decrease in strength with decreasing brightness. The equivalent widths of the emission components of the MgII h and k lines show no systematic variation with decreasing brightness. These results are similar to what has been found in the visual part of the spectrum HR 5999 for the FeII (4923 A) and NaI D absorption lines and for the H-alpha emission, respectively.