This proposal will help answer two major open questions in the field of star formation: 1) What causes a particular region of a molecular cloud to attain high densities on the way to forming a star cluster? 2) What is the physical structure of such ..pre-star-cluster massive clumps?
We plan to study the structure and kinematics of the envelope and the dense gas in four massive (M > 100 M_sun) pre-star-cluster clumps embedded in Infrared Dark Clouds. The selected objects have physical and chemical properties which resemble scaled-up versions of low-mass pre-stellar cores (they are cold, dense and show large abundances of deuterated molecules). They are also dark at 24&70 micron within the Herschel beam in Band 1. Therefore, they are the ideal targets where to study the initial conditions in the process of high-mass and stellar cluster formation.
We plan to simultaneosly observe ortho-H2O(1_10-1_01) (in absorption) and ortho-NH3(1_1-0_1) (in emission) to study the kinematics of the clump and the embedded dense cores. These results will also be compared to recent work toward low-mass pre-stellar cores to study how different environments affect the chemistry and the dynamical evolution of the earliest stages of star formation.
We also plan to observe CO(8-7), (9-8) and (10-9) to investigate if turbulence dissipation and shocks play an important role in the formation of dense cores and fragmentation of massive clumps. These observations are based on comprehensive MHD shock and PDR model predictions.
Publication
Mid-J CO shock tracing observations of infrared dark clouds. I. . Pon A. et al. . Astronomy & Astrophysics, Volume 577, id.A75, 12 pp. . 577 . 10.1051\/0004-6361\/201525681 . 2015A&A...577A..75P ,
Instrument
HIFI_HifiPoint_pos, HIFI_HifiMapping_fly
Temporal Coverage
2012-04-25T19:17:11Z/2012-11-03T01:23:50Z
Version
SPG v14.1.0
Mission Description
Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
European Space Agency, 2013, Unveiling The Initial Conditions Of High-Mass Star And Stellar Cluster Formation, SPG v14.1.0, European Space Agency, https://doi.org/10.5270/esa-527q70x
