Detection of a warm molecular wind in DG Tauri

M. Takami*, A. Chrysostomou, T. P. Ray, C. Davis, W. R F Dent, J. Bailey, M. Tamura, H. Terada

*Corresponding author for this work

    Research output: Contribution to journalArticle

    36 Citations (Scopus)

    Abstract

    We detect near-infrared H2 emission in DG Tau using the Infrared Camera and Spectrograph (IRCS) on the 8.2-m SUBARU telescope. The spectra obtained along the jet axis show that the centroidal position of the 1-0 S(1) emission is offset by 0.2″ from the star towards the jet, while those obtained perpendicular to the jet axis show a marginal extension, indicating that the emission line region has a typical width of ∼0.6″. Their line profiles show a peak velocity of ∼15 km s-1 blueshifted from the systemic velocity. These results indicate that the emission originates from a warm molecular wind with a flow length and width of ∼40 and ∼80 AU, respectively. The line flux ratios (I1-0S(0)/I1-0S(1) and an upper limit for I2-1S(1)/I1-0S(1)) suggest that the flow is thermalized at a temperature of ∼2000 K, and is likely heated by shocks or ambipolar diffusion. The observed velocity and spatial extension suggest that the H2 and forbidden line emission originate from different components of the same flow, i.e., a fast and partially ionised component near the axis and a slow molecular component surrounding it. Such a flow geometry agrees with model predictions of magneto-centrifugal driven winds.

    Original languageEnglish
    Pages (from-to)213-219
    Number of pages7
    JournalAstronomy and Astrophysics
    Volume416
    Issue number1
    DOIs
    Publication statusPublished - Mar 2004

    Keywords

    • ISM: jets and outflows
    • Line: formation
    • Stars: pre-main sequence

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