[FE-II] 1.53-MICRON AND 1.64-MICRON EMISSION FROM PRE-MAIN-SEQUENCE STARS

We present flux-calibrated profiles of the [Fe II] 1.53 and 1.64 mu m lines in five pre-main-sequence stars, PV Cep, V1331 Cyg, R Mon, and D G and HL Tau. The line centroids are blueshifted in all five sources, and four of the five have only blueshifted flux. In agreement with pre vious studies, we attribute the line asymmetries to local obscuration by dusty circumstellar disks. The absence of redshifted flux implies a minimum column density of obscuring material. The largest limit, N-H > 3 X 10(22) Cm-2, derived for V1331 Cyg, suggests disk surface densit ies greater than 0.05 g cm(-2) and disk masses greater than 0.001 M. w ithin a radius of similar to 200 AU. The narrow high-velocity lines in PV Cep, V1331 Cyg, and HL Tau require formation in well collimated wi nds. The maximum full opening angles of their winds range from less th an 20 degrees in V1331 Cyg to less than 40 degrees in HL Tau. The [Fe II] data also yield estimates of the electron densities (n(e) similar to 10(4) cm(-3)), hydrogen ionization fractions (f(H+) similar to 1/3) , mass-loss rates (similar to 10(-7) to 2 x 10(-6) M. yr(-1)), and cha racteristic radii of the emitting regions (similar to 32 to similar to 155 AU). The true radial extents will be larger, and the mass-loss ra tes smaller, by factors of a few for the outflows with limited opening angles. In our small sample the higher mass stars have stronger lines , larger emitting regions, and greater mass-loss rates. These differen ces are probably limited to the scale and energetics of the envelopes, because the inferred geometries, kinematics and physical conditions a re similar. The measured [Fe II] profiles sample both ''high''- and '' low''-velocity environments. Recent studies indicate that these region s have some distinct physical properties and may be spatially separate , The [Fe II] data show that similar sizes and densities can occur in both environments.