Emission-Line Studies of Young Stars. III. Correlations with the Infrared Excess

The IR luminosity excesses and Ca II triplet line strengths of a sample of 85 T Tauri and Herbig Ae/Be stars are compared using published photometry and new emission-line data. It is found that the Ca II triplet and IR excess luminosities are correlated over 5 decades, but the interpretation in terms of accretion is not straightforward. The IR excesses are also examined to see whether there is sufficient IR luminosity (compared to the star) to require accretion as an additional energy source. The IR spectral density distributions are further examined, and estimates of the intrinsic stellar radii and bolometric luminosities are derived; some of the uncertainties caused by reflected light and unresolved IR companions are illustrated.