From clouds to protoplanetary disks: the astrochemical link

4-8 October 2015
Hans Harnack Haus
Europe/Berlin timezone
Home > Timetable > Session details > Contribution details

Poster session

Mass accretion flows in the high-mass star forming complex NGC6334

Speakers

• Dr. Alvaro SANCHEZ-MONGE

Content

The formation of high-mass stars is one of the major topics of astrophysical research, in particular the process of accretion from large-scale clouds (a few 10 pc) down to small-scale cores (a few 0.01 pc). We have selected the nearby high-mass star forming complex NGC6334 to study the gas velocities at different scales and probe the infall rates onto the protostellar cores embedded in the molecular cloud. In particular, we focus on the two protostellar clusters NGC6334-I and I(N), which are the brightest sources in the complex and show different stages of evolution. This study makes use of submillimeter observations conducted with single-dish telescopes (e.g. APEX) and interferometers (e.g. SMA), complemented with 3D numerical non-LTE radiative transfer modeling.

NGC6334 is a high-mass star forming complex that lies in the Carina-Sagittarius arm in the Galactic plane, at a distance of only 1.3 kpc. At large scales, the cloud has a filamentary structure that extends for 30 pc, with a total mass and luminosity of $10^4$-$10^5$$M_\odot and 10^5-10^6$$L_\odot$, respectively. Our APEX observations of dense gas tracers reveal a velocity field with a gradient of 0.07 km s$^{-1}$pc$^{-1}$ that can be interpreted as the imprint of the original rotation of the molecular cloud. The mass accretion rate throughout the filament is $10^{-5}$ $M_\odot$ yr$^{-1}$, with values as high as a few $10^{-3}$ $M_\odot$ yr$^{-1}$ towards particular positions of the cloud such as sources I and I(N). These values are in agreement with the infall rates obtained from our 3D radiative transfer modeling: We have used RADMC-3D and LIME to model the line shapes of different HCN, CO and CS transitions, taking into account the spatial distribution of the dense cores, HII regions and outflows. The best fit results in mass accretion rates in the order of $10^{-3}$ $M_\odot$ yr$^{-1}$ for the clumps and $10^{-4}$ $M_\odot$ yr$^{-1}$ for the cores.