2019A&A...628A..98B -
Astronomy and Astrophysics, volume 628A98-98 (2019/8-1)
A multi-molecular line study of the star-forming globule CB88-230.
BRAND J., WOUTERLOOT J.G.A., CODELLA C., MASSI F. and GIANNETTI A.
Abstract (from CDS):
Context. This paper relates to low-mass star formation in globules, and the interaction of newly-formed stars with their environment. We follow up on the results of our earlier observations of this globule.
Aims. Our aim is to study the gas- and dust environment of the young stellar object (YSO) in globule CB88 230, the large-scale molecular outflow triggered by the jet driven by the YSO, and their interaction.
Methods. We carried out submillimetre continuum and multi-line molecular observations with several single-dish facilities, mapping the core of the globule and the large-scale outflow associated with the YSO. Results. Dust continuum and molecular line maps (of 12CO, C18O, CS, CH3OH) show a flattened (axes ratio 1.5-1.7), asymmetric core with a full width at half maximum (FWHM)-diameter of 0.16-0.21pc. Line profiles of 12CO, 13CO(2-1, 3-2), and CS(2-1) show self-absorption near the YSO; the absorption dip is at a slightly (∼0.3km/s) redder velocity than that of the quiescent gas, possibly indicating infall of cooler envelope gas. The mass of the core, determined from C18O(1-0) observations, is about 8M☉, while the virial mass is in the range 5-8M☉, depending on the assumed density distribution. We detect a slight velocity gradient (∼0.98km/s/pc), though rotational energy is negligible with respect to gravitational and turbulent energy of the core. A fit to the spectral energy distribution of the core gives a dust temperature Td~=18K and a gas mass of ca. 2M☉ (assuming a gas-to-dust ratio of 100). More careful modelling of the sub-mm emission (not dominated by the relatively hot central regions) yields M~=8M☉. From the molecular line observations we derive gas temperatures of 10-20K. A Bayesian analysis of the emission of selected molecules observed towards the YSO, yields Tkin~=21.4K (68% credibility interval 14.5-35.5K) and volume density n(H2)~=4.6x105cm–3 (8.3x104-9.1x105cm–3). We have mapped the well-collimated large-scale outflow in 12CO(3-2). The outflow has a dynamical age of a few 104yr, and contains little mass (a few 10–2M☉). A misalignment between the axis of this large-scale outflow and that of the hot jet close to the YSO indicates that the outflow direction may be changing with time.
Abstract Copyright:
© ESO 2019
Journal keyword(s):
stars: formation - stars: pre-main sequence - ISM: clouds - ISM: jets and outflows - ISM: individual objects: CB88-230
Simbad objects:
15
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2019A&A...628A..98B and select 'bookmark this link' or equivalent in the popup menu