Wind-Disk-Ambient Cloud Interactions in the Near Environment of T Tauri

Abstract

view Abstract Citations (48) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Wind-Disk-Ambient Cloud Interactions in the Near Environment of T Tauri Herbst, T. M. ; Robberto, M. ; Beckwith, S. V. W. Abstract Fabry-Perot images of the near environment of T Tauri taken in the 2.122μm, υ = 1-0 S(1) quadrupole emission line of molecular hydrogen reveal a complex system of interlocking loops and arcs within 15" of the central stars. Long slit echelle spectra in the S(1) transition at several position angles indicate that the kinematics of the gas is also complex. To the north of T Tau, the redshift of the H2 line increases linearly with distance. Lower resolution spectra covering the entire K and H photometric bands reveal shock excited H2 and Fe II throughout the region. Model fits to the molecular lines point to a constant or slightly decreasing excitation temperature with distance from the stars. The interaction with the ambient molecular cloud of two, almost perpendicular outflow systems can explain the complex molecular hydrogen morphology of T Tau. Orbital motion may produce the apparent curvature of the structures. The NW-SE outflow probably energizes Burnharn's Nebula to the south of the stars. This region contains several molecular hydrogen arcs resembling bow shocks opening back toward T Tau. Similar arcs, seen in previously published [S II] images, lie interior to the H2, signalling the presence of a magnetic precursor to the shocks. The radial velocities and velocity dispersion in Burnham's Nebula remain enigmatic, however. Spatially resolved near- and mid-infrared photometry of the binary reveals evidence for circumstellar disks in both stars. These disks may collimate the outflows responsible for the H2, [S II], and [Fe II] structures. The spectral energy distribution of the infrared companion has a strong silicate absorption near 10μm, while the primary shows the silicate feature in emission. This result resolves earlier contradictory observations, some of which showed little or no Si emission in the primary. After subtraction of a model photosphere plus disk, the companion's absorption feature appears somewhat wider than the primary's emission line, consistent with optical depth or particle size effects expected from the photometric properties of the stars. The model stellar radius of the visible primary, coupled with published V sin i observations, imply an inclination of the T Tauri system of l9°. Publication: The Astronomical Journal Pub Date: August 1997 DOI: 10.1086/118508 Bibcode: 1997AJ....114..744H Keywords: STARS: PRE-MAIN SEQUENCE; CIRCUMSTELLAR MATTER; ISM: KINEMATICS AND DYNAMICS full text sources ADS | data products SIMBAD (5)