Astronomy and Astrophysics, volume 569A, 7-7 (2014/9-1)
The Earliest Phases of Star formation (EPoS). Temperature, density, and kinematic structure of the star-forming core CB 17.
SCHMALZL M., LAUNHARDT R., STUTZ A.M., LINZ H., BOURKE T.L., BEUTHER H., HENNING T., KRAUSE O., NIELBOCK M. and SCHMIEDEKE A.
Abstract (from CDS):
The initial conditions for the gravitational collapse of molecular cloud cores and the subsequent birth of stars are still not well constrained. The characteristic cold temperatures (∼10K) in such regions require observations at sub-millimetre and longer wavelengths. The Herschel Space Observatory and complementary ground-based observations presented in this paper have the unprecedented potential to reveal the structure and kinematics of a prototypical core region at the onset of stellar birth. This paper aims to determine the density, temperature, and velocity structure of the star-forming Bok globule CB17. This isolated region is known to host (at least) two sources at different evolutionary stages: a dense core, SMM1, and a Class I protostar, IRS. We modeled the cold dust emission maps from 100µm to 1.2mm with both a modified blackbody technique to determine the optical depth-weighted line-of-sight temperature and column density and a ray-tracing technique to determine the core temperature and volume density structure. Furthermore, we analysed the kinematics of CB17 using the high-density gas tracer N2H+. From the ray-tracing analysis, we find a temperature in the centre of SMM1 of T0=10.6K, a flat density profile with radius 9.5x103au, and a central volume density of nH,0=2.3x105cm–3. The velocity structure of the N2H+ observations reveal global rotation with a velocity gradient of 4.3km/s/pc. Superposed on this rotation signature we find a more complex velocity field, which may be indicative of differential motions within the dense core. SMM is a core in an early evolutionary stage at the verge of being bound, but the question of whether it is a starless or a protostellar core remains unanswered.
dust, extinction - ISM: molecules - ISM: kinematics and dynamics - stars: formation - stars: low-mass - ISM: individual objects: CB 17
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<Available at CDS (J/A+A/569/A7): list.dat fits/*>
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