DK Cha is an intermediate-mass star in transition from an embedded configuration to a star plus disk stage. We aim to study the composition and energetics of the circumstellar material during this pivotal stage. Using the Range Scan mode of PACS on t
he Herschel Space Observatory, we obtained a spectrum of DK Cha from 55 to 210 micron as part of the DIGIT Key Program. Almost 50 molecular and atomic lines were detected, many more than the 7 lines detected in ISO-LWS. Nearly the entire ladder of CO from J=14-13 to 38-37 (E_u/k = 4080 K), water from levels as excited as E_u/k = 843 K, and OH lines up to E_u/k = 290 K were detected. The continuum emission in our PACS SED scan matches the flux expected from a model consisting of a star, a surrounding disk of 0.03 Solar mass, and an envelope of a similar mass, supporting the suggestion that the object is emerging from its main accretion stage. Molecular, atomic, and ionic emission lines in the far-infrared reveal the outflows influence on the envelope. The inferred hot gas can be photon-heated, but some emission could be due to C-shocks in the walls of the outflow cavity.
An updated Science Vision for the SOFIA project is presented, including an overview of the characteristics and capabilities of the observatory and first generation instruments. A primary focus is placed on four science themes: The Formation of Stars
and Planets, The Interstellar Medium of the Milky Way, Galaxies and the Galactic Center and Planetary Science.
