C18O (3-2) observations of the Cometary Globule CG 12: a cold core and a C18O hot spot

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    Abstract

    The feasibility of observing the C18O (3-2) spectral line in cold
    clouds with the APEX telescope has been tested. As the line at 329.330
    GHz lies in the wing of a strong atmospheric H2O absorption it can be
    observed only at high altitude observatories. Using the three lowest
    rotational levels instead of only two helps to narrow down the
    physical properties of dark clouds and globules. The centres of two
    C18O maxima in the high latitude low mass star forming region CG 12
    were mapped in C18O (3-2) and the data were analyzed together with
    spectral line data from the SEST. The TMB (3-2)/TMB (2-1) ratio in the
    northern C18O maximum, CG 12-N, is 0.8, and in the southern maximum,
    CG 12-S, 2. CG 12-N is modelled as a 120´´ diameter (0.4 pc) cold core
    with a mass of 27 Msun. A small size maximum with a narrow, 0.8 km s^-1,
    C18O (3-2) spectral line with a peak temperature of TMB 11 K
    was detected in CG 12-S. This maximum is modelled as a 60"-80"
    diameter ( 0.2 pc) hot (80 K < Tex < 200 K) 1.6 Msun clump. The source
    lies on the axis of a highly collimated bipolar molecular outflow near
    its driving source. This is the first detection of such a compact,
    warm object in a low mass star forming region.

    Original languageEnglish
    JournalAstronomy & Astrophysics
    Volume454
    Issue number2
    Pages (from-to)L71-L74
    Number of pages4
    ISSN0004-6361
    DOIs
    Publication statusPublished - 2006
    MoE publication typeA1 Journal article-refereed

    Fields of Science

    • 115 Astronomy, Space science
    • clouds: ISM molecules
    • ISM: structure
    • ISM: radio lines
    • ISM: individual objects: CG 12, NGC5367

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