The small--scale structure and kinematics of B335

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Session 39 -- Interferometry II
Oral presentation, Tuesday, 2:00-6:30, Zellerbach Playhouse Room

[39.03] The small--scale structure and kinematics of B335

C. J. Chandler (Caltech), A. I. Sargent (Caltech)

\noindent High--resolution (5$''$) observations of B335 in $^{13}$CO(1--0), C$^{18}$O(1--0) and 2.7 mm continuum using the Owens Valley Millimeter Array reveal the small--scale structure of gas and dust in the cloud core. The 2.7 mm continuum emission is centered on the embedded far--infrared source, and is extended perpendicular to the molecular outflow. By combining our data with existing measurements we find that the central source is well--described by a two--component model, with a uniform source of radius $125 \pm 50$ AU (possibly a disk) and an infall envelope with $\rho \propto r^{-3/2}$.

The optically thick $^{13}$CO traces the outflow already detected in lower--resolution $^{12}$CO(1--0) measurements to within 1000 AU of the star. Emission in the C$^{18}$O isotope is less optically thick, and shows emission associated with both the outflow and the cloud core. A spectrum of $^{13}$CO(1--0) integrated over the central 5$''$ shows the classic asymmetric profile associated with infall, while the C$^{18}$O(1--0) line is centered on the systemic velocity.

Our line and continuum results combine to support the suggestion by Zhou et al.\ (1993, ApJ 404 232) that the inner cloud core is still undergoing collapse.

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