NAOC Open IR
Probing the initial conditions of high-mass star formation: IV. Gas dynamics and NH2D chemistry in high-mass precluster and protocluster clumps
Zhang, Chuan-Peng1,2,3; Li, Guang-Xing4; Pillai, Thushara5; Csengeri, Timea6; Wyrowski, Friedrich6; Menten, Karl M.6; Pestalozzi, Michele R.7
2020-06-23
Source PublicationASTRONOMY & ASTROPHYSICS
ISSN0004-6361
Volume638Pages:26
AbstractContext. The initial stage of star formation is a complex area of study because of the high densities (nH2 > 106 cm-3) and low temperatures (Tdust < 18 K) involved. Under such conditions, many molecules become depleted from the gas phase by freezing out onto dust grains. However, the deuterated species could remain gaseous under these extreme conditions, which would indicate that they may serve as ideal tracers.Aims. We investigate the gas dynamics and NH2D chemistry in eight massive precluster and protocluster clumps (G18.17, G18.21, G23.97N, G23.98, G23.44, G23.97S, G25.38, and G25.71).Methods. We present NH2D 111-101 (at 85.926 GHz), NH3 (1, 1), and (2, 2) observations in the eight clumps using the PdBI and the VLA, respectively. We used 3D GAUSSCLUMPS to extract NH2D cores and provide a statistical view of their deuterium chemistry. We used NH3 (1, 1) and (2, 2) data to investigate the temperature and dynamics of dense and cold objects.Results. We find that the distribution between deuterium fractionation and kinetic temperature shows a number density peak at around Tkin = 16.1 K and the NH2D cores are mainly located at a temperature range of 13.0 to 22.0 K. The 3.5 mm continuum cores have a kinetic temperature with a median width of 22.1 4.3 K, which is obviously higher than the temperature in NH2D cores. We detected seven instances of extremely high deuterium fractionation of 1.0 Dfrac <= 1.41. We find that the NH2D emission does not appear to coincide exactly with either dust continuum or NH3 peak positions, but it often surrounds the star-formation active regions. This suggests that the NH2D has been destroyed by the central young stellar object (YSO) due to heating. The detected NH2D lines are very narrow with a median width of 0.98 +/- 0.02 km s-1, which is dominated by non-thermal broadening. The extracted NH2D cores are gravitationally bound (alpha vir < 1), they are likely to be prestellar or starless, and can potentially form intermediate-mass or high-mass stars in future. Using NH3 (1, 1) as a dynamical tracer, we find evidence of very complicated dynamical movement in all the eight clumps, which can be explained by a combined process with outflow, rotation, convergent flow, collision, large velocity gradient, and rotating toroids.Conclusions. High deuterium fractionation strongly depends on the temperature condition. Tracing NH2D is a poor evolutionary indicator of high-mass star formation in evolved stages, but it is a useful tracer in starless and prestellar cores.
Keywordstars: formation techniques: interferometric ISM: clouds methods: observational
Funding OrganizationNational Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany
DOI10.1051/0004-6361/201936118
WOS KeywordH-II REGIONS ; DEUTERIUM FRACTIONATION ; MOLECULAR CLOUD ; TRIGONOMETRIC PARALLAXES ; HYPERFINE-STRUCTURE ; DEUTERATED AMMONIA ; DARK CLOUDS ; DENSE CORES ; CATALOG ; N2H+
Language英语
Funding ProjectNational Natural Science Foundation of China[11703040] ; National Key Basic Research Program of China (973 Program)[2015CB857101] ; NAOC Nebula Talents Program ; China Scholarship Council in Germany[201704910137]
Funding OrganizationNational Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Basic Research Program of China (973 Program) ; National Key Basic Research Program of China (973 Program) ; NAOC Nebula Talents Program ; NAOC Nebula Talents Program ; China Scholarship Council in Germany ; China Scholarship Council in Germany
WOS Research AreaAstronomy & Astrophysics
WOS SubjectAstronomy & Astrophysics
WOS IDWOS:000545013800001
PublisherEDP SCIENCES S A
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Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/82871
Collection中国科学院国家天文台
Corresponding AuthorZhang, Chuan-Peng
Affiliation1.Chinese Acad Sci, Natl Astron Observat, Beijing 100101, Peoples R China
2.Chinese Acad Sci, Natl Astron Observ, CAS Key Lab FAST, Beijing 100101, Peoples R China
3.Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany
4.Yunnan Univ, South Western Inst Astron Res, Kunming 650500, Yunnan, Peoples R China
5.Boston Univ, Inst Astrophys Res, 725 Commonwealth Ave, Boston, MA 02215 USA
6.Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany
7.Ist Fis Spazio Interplanetario INAF, Via Fosso Cavaliere 100, I-00133 Rome, Italy
Recommended Citation
GB/T 7714
Zhang, Chuan-Peng,Li, Guang-Xing,Pillai, Thushara,et al. Probing the initial conditions of high-mass star formation: IV. Gas dynamics and NH2D chemistry in high-mass precluster and protocluster clumps[J]. ASTRONOMY & ASTROPHYSICS,2020,638:26.
APA Zhang, Chuan-Peng.,Li, Guang-Xing.,Pillai, Thushara.,Csengeri, Timea.,Wyrowski, Friedrich.,...&Pestalozzi, Michele R..(2020).Probing the initial conditions of high-mass star formation: IV. Gas dynamics and NH2D chemistry in high-mass precluster and protocluster clumps.ASTRONOMY & ASTROPHYSICS,638,26.
MLA Zhang, Chuan-Peng,et al."Probing the initial conditions of high-mass star formation: IV. Gas dynamics and NH2D chemistry in high-mass precluster and protocluster clumps".ASTRONOMY & ASTROPHYSICS 638(2020):26.
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