WFPC2 Studies of the Disk and Jet of HH 30

Abstract

Hubble Space Telescope imaging of HH 30 has revealed this object to be a prototype young stellar object (YSO) accretion disk system. An optically thick circumstellar absorption disk, 450 AU in diameter, is seen extending perpendicular to highly collimated bipolar jets. The jet width is resolved in the transverse direction and increases with distance from the central star. The size and age of the disk compare well to the early solar nebula during planet formation. HH 30 is the first YSO disk ever observed at 14 AU resolution, and the first viewed close enough to edge-on that the vertical structure of the disk is clearly visible. These HST images of HH 30 offer the first-ever opportunity to directly measure the flaring profile of an astrophysical accretion disk. We have compared the images to model nebulosities calculated in both multiple and single scattering regimes, in the latter case via chi-squared minimization. This analysis constrains the circumstellar density distribution and grain scattering properties. A brief summary of the results is presented here; full details and references appear in Burrows et al., Ap.J. (1996).