WFPC-2 Observations of the Circumstellar Nebulosity of T Tau and HL Tau
Session 16 -- Molecular Clouds, Star Formation, Very Young Stars, T Tauri Stars
Oral presentation, Monday, 30, 1994, 10:00-11:30

[16.06] WFPC-2 Observations of the Circumstellar Nebulosity of T Tau and HL Tau

Karl R. Stapelfeldt (JPL), C. J. Burrows (STSci), J. Krist (STSci), J. Trauger (JPL), G. Ballester (Michigan), S. Casertano (Johns Hopkins), J. Clarke (Michigan), D. Crisp (JPL), J. Gallagher (Wisconsin), R. Griffiths (Johns Hopkins), J. Hester (Arizona State), J. Hoessel (Wisconsin), J. Holtzman (Lowell), J. Mould (Mt. Stromlo), P. Scowen (Arizona State) (A. Watson) (Wisconsin), J. Westphal (Caltech)

T Tauri lies on an arc of reflection nebulosity which extends approximately 3$^{\prime\prime}$ N and 2$^{\prime\prime}$ SW from the star. This nebula has a characteristic width of 0.5$^{\prime\prime}$, is concave open toward the nearby Burnham's Nebula, and is closely aligned with the optical polarization vector of the system. The morphology T Tau's edge-brightened cometary nebula is similar to models of scattered light from a flared, optically thick disk observed from 45 degrees above the equator plane. No optical counterpart to the infrared companion is seen to a limiting magnitude of V= 23.

WFPC2 images of HL Tauri show that this object is entirely reflection nebulosity at optical wavelengths. No stellar source is visible to a limiting magnitude of V$=$ 26, a result which dictates a significant upward revision of the luminosity and mass estimates for HL Tau. The V-I color of the nebula is dominated by foreground extinction, with only small internal color changes. The bright core of the nebula has an east-west elongation of 1$^{\prime\prime}$ and has an unusual morphology. We will discuss the implications of these results for i). HL Tau's stellar type and ii). models for the distribution of the circumstellar matter.