The Mg 2 lines as diagnostic of PMS nature in Herbig Ae/Be stars

摘要

The main objective of this program was to observe some newly discovered and previously unobserved Herbig Ae/Be (HAeBE) stars with IUE. A previous archival study suggested that there was a full range of profiles in the Mg 2 lines for these objects; ranging from the double peak emission to the narrow absorption lines. We have found by studying the IUE data of main sequence B and classical Be stars that the P Cygni profiles in the Mg 2 lines in HAeBe stars are truly unique and are the signature of accelerating winds in their extended circumstellar material. We argue, for the purposes of this proposal, that the structure of the Mg 2 lines was a superior diagnostic of the dynamical activity and ultimately of the PMS nature of these objects. This program was a follow up study of several interesting intermediate-mass stars with the goal of classifying these objects based on the shape of their Mg 2 lines.