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primary topic: Chemical Substructure of High Mass Star Forming Regions

Chemical Substructure of High Mass Star Forming Regions
type: Article
abstract: High mass stars (stars with mass M > 8 Msolar) are one of the most fundamental building blocks in the Universe. Deeply embedded in the dense clouds at further distances than their low mass counterparts, the forming processes of these fast evolving objects are still unclear. In the earliest phases of the high mass star forming regions (HMSFRs), many complicated astrophysical processes, such as fragmentation, accretion, inflows and outflows are coexistent that dynamic studies are not enough to understand all the mysteries. Therefore, chemistry has developed into a powerful tool in probing the nature of them. With the aim of understanding the chemical and physical processes in the very beginning of high mass star formation, I selected a series of HMSFRs at different evolutionary stages, and studied their chemical-physical properties via high spatial resolution observations at (sub)mm wavelengths. The results can be summarised shortly as follows: 1. At a spatial resolution of < 1500 AU, fragmentation process is observed in the continuum maps of all the resolved sources. Above all, the fragments in 4 starless clumps are on average more massive (with M > 10 Msolar) than the Jeans mass of the large-scale clump, indicating that thermal motions is not the dominant support to against collapse, and high mass stars may form in a “scaled up” version similar to the low mass stars. 2. Observations at a spatial resolution of 1 000 AU resolve NGC 7538 S into at least 3 fragments, having comparable sizes and masses derived from continuum emissions. However, these fragments exhibit distinguishing spectral line emissions at 1.3 mm wavelength, revealing different evolutionary stages. Combing with a 1-D gas-grain model fitting, for the first time, this project suggests that these fragments may result from different warm-up paces after synchronised fragmentation, and that the warm-up processes from one stage to another is rapid. 3. Chemical variations at small scales may be caused by the …
date: 2015
author list: authors
type: EPrint
type: DoctoralThesisEPrint
is part of: repository
has document: Chemical Substructure of High Mass Star Forming Regions (Other)
has document: Chemical Substructure of High Mass Star Forming Regions (PDF)
subject: 520 Astronomie
subject: 530 Physik
subject: 540 Chemie

Chemical Substructure of High Mass Star Forming Regions (PDF)
type: Document
has file: Thesis_syfeng_MPIA(1).pdf
has part: Thesis_syfeng_MPIA(1).pdf

Siyi Feng
type: Person
given name: Siyi
family name: Feng

Chemical Substructure of High Mass Star Forming Regions (Other)
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Chemical Substructure of High Mass Star Forming Regions (Other)
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Chemical Substructure of High Mass Star Forming Regions (Other)
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Chemical Substructure of High Mass Star Forming Regions (Other)
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primary topic: Chemical Substructure of High Mass Star Forming Regions

520 Astronomie
type: Concept
preferred label: 520 Astronomy and allied sciences @en

530 Physik
type: Concept
preferred label: 530 Physics @en

540 Chemie
type: Concept
preferred label: 540 Chemistry and allied sciences @en