Dust, Ice, and Gas In Time (DIGIT) Herschel program first results A full PACS-SED scan of the gas line emission in protostar DK Chamaeleontis

Dullemond, C. P.

Abstract

Aims. We aim to study the composition and energetics of the circumstellar material of DK Cha, an intermediate-mass star in transition from an embedded configuration to a star plus disk stage, during this pivotal stage of its evolution. Methods. Using the range scan mode of PACS on the Herschel Space Observatory, we obtained a spectrum of DK Cha from 55 to 210 mu m as part of the DIGIT key program. Results. 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 J(K-1K+1) = 7(07) (E(u)/k = 843 K), and OH lines up to E(u)/k = 290 K were detected. Conclusions. The continuum emission in our PACS SED scan matches the flux expected by a model consisting of a star, a surrounding disk of 0.03 M(circle dot), 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 outflow's influence on the envelope. The inferred hot gas may be photon-heated, but some emission may be caused by C-shocks in the walls of the outflow cavity.

Más información

Título según WOS: ID WOS:000281527200129 Not found in local WOS DB
Título de la Revista: ASTRONOMY & ASTROPHYSICS
Volumen: 518
Editorial: EDP SCIENCES S A
Fecha de publicación: 2010
DOI:

10.1051/0004-6361/201014686

Notas: ISI