2021A&A...653A.108S -
Astronomy and Astrophysics, volume 653A, 108-108 (2021/9-1)
Globules and pillars in Cygnus X. III. Herschel and upGREAT/SOFIA far-infrared spectroscopy of the globule IRAS 20319+3958 in Cygnus X.
SCHNEIDER N., ROLLIG M., POLEHAMPTON E.T., COMERON F., DJUPVIK A.A., MAKAI Z., BUCHBENDER C., SIMON R., BONTEMPS S., GUSTEN R., WHITE G., OKADA Y., PARIKKA A. and ROTHBART N.
Abstract (from CDS):
IRAS 20319+3958 in Cygnus X South is a rare example of a free-floating globule (mass ∼240M
☉, length ∼1.5pc) with an internal HII region created by the stellar feedback of embedded intermediate-mass stars, in particular, one Herbig Be star. In Schneider et al. (
2012A&A...542L..18S) and Djupvik et al. (
2017A&A...599A..37D), we proposed that the emission of the far-infrared (FIR) lines of [CII] at 158µm and [OI] at 145µm in the globule head are mostly due to an internal photodissociation region (PDR). Here, we present a Herschel/HIFI [CII] 158 µm map of the whole globule and a large set of other FIR lines (mid-to high-J CO lines observed with Herschel/PACS and SPIRE, the [OI] 63 µm line and the
12CO 16-15 line observed with upGREAT on SOFIA), covering the globule head and partly a position in the tail. The [CII] map revealed that the whole globule is probably rotating. Highly collimated, high-velocity [CII] emission is detected close to the Herbig Be star. We performed a PDR analysis using the KOSMA-τ PDR code for one position in the head and one in the tail. The observed FIR lines in the head can be reproduced with a two-component model: an extended, non-clumpy outer PDR shell and a clumpy, dense, and thin inner PDR layer, representing the interface between the HII region cavity and the external PDR. The modelled internal UV field of ∼2500Go is similar to what we obtained from the Herschel FIR fluxes, but lower than what we estimated from the census of the embedded stars. External illumination from the ∼30pc distant Cyg OB2 cluster, producing an UV field of ∼150-600Go as an upper limit, is responsible for most of the [CII] emission. For the tail, we modelled the emission with a non-clumpy component, exposed to a UV-field of around 140Go.
Abstract Copyright:
© ESO 2021
Journal keyword(s):
ISM: atoms - ISM: clouds - HII regions - photon-dominated region - ISM: molecules - ISM: kinematics and dynamics
VizieR on-line data:
<Available at CDS (J/A+A/653/A108): list.dat fits/*>
Status at CDS
:
Examining the need for a new acronym.
Simbad objects:
6
Full paper
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