We have obtained high-resolution spectra of the Brγ emission line in a small sample of low-luminosity embedded young stellar objects (YSOs) and active T Tauri stars. We find line profiles which possess broad wings (400-700 km s-1 FWZI) but which conspicuously lack the blueshifted absorption components generally expected for emission from a wind. Even T Tauri stars that show strong wind absorption features in the Hα and Na D lines show no obvious evidence of a wind origin for the Brγ line. These results imply that the winds in these YSOs are likely cooler than previously estimated and that mass-loss rates derived from Brγ line strengths require reexamination. We also find a tendency for the centroid of the emission to be blueshifted with respect to the stellar velocity, as is often observed in the higher Balmer lines of T Tauri stars. This tendency is generally consistent with emission from infalling rather than outflowing gas. We discuss the physical origin of the infalling gas and the origin of the broad line wings.
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Najita et al. (1996) studied this question.