Dust, Ice, and Gas in Time (DIGIT) Herschel program first results

T. A. Van Kempen, J. D. Green, N. J. Evans, E. F. Van Dishoeck, L. E. Kristensen, G. J. Herczeg, B. Merín, J. E. Lee, J. K. Jørgensen, J. Bouwman, B. Acke, M. Adamkovics, J. C. Augereau, E. Bergin, G. A. Blake, J. M. Brown, J. S. Carr, J. H. Chen, L. Cieza, C. DominikC. P. Dullemond, M. M. Dunham, A. Glassgold, M. Güdel, P. M. Harvey, Th Henning, M. R. Hogerheijde, D. Jaffe, H. J. Kim, C. Knez, J. H. Lacy, S. Maret, G. Meeus, R. Meijerink, G. D. Mulders, L. Mundy, J. Najita, J. Olofsson, K. M. Pontoppidan, C. Salyk, B. Sturm, R. Visser, L. B.F.M. Waters, C. Waelkens, U. A. Yildiz

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

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 μm 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 (Eu/k = 4080 K), water from levels as excited as JK-1K+1 = 707 (E u/k = 843 K), and OH lines up to Eu/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 , 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.

Original languageEnglish
Article numberL128
JournalAstronomy and Astrophysics
Volume518
Issue number7-8
DOIs
StatePublished - 16 Jul 2010
Externally publishedYes

Keywords

  • Astrochemistry
  • Circumstellar matter
  • Infrared: ISM
  • Stars: formation
  • Stars: protostars
  • Submillimeter: ISM

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