Possible Habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in the Initial Conditions of High-mass Star Formation  

作　　者：Quan-Ling Cui Chuan-Peng Zhang Jun-Jie Wang 

机构地区：[1]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]College of Science,Qiqihar University,Qiqihar 161006,China [4]Guizhou Radio Astronomical Observatory,Guizhou University,Guiyang 550000,China

出　　处：《Research in Astronomy and Astrophysics》2024年第4期237-252,共16页天文和天体物理学研究（英文版）

基　　金：supported by the National Key R&D Program of China(No.2022YFA1602901);the local Science and Technology innovation projects of the central government(No.XZ202301YD0037C);the National Natural Science Foundation of China(NSFC,grant No.11933011)。

摘　　要：The initial condition of high-mass star formation is a complex area of study because of the high densities(n_(H_(2))>106cm^(-3))and low temperatures(T_(dust)<18 K)involved.Under such conditions,many molecules become depleted from the gas phase by freezing out onto dust grains.However,the N-bearing and deuterated species could remain gaseous under these extreme conditions,suggesting that they may serve as ideal tracers.In this paper,using the Plateau de Bure Interferometer and Very Large Array observations at 1.3 mm,3.5 mm,and 1.3 cm,we investigate the possible habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in eight massive precluster and protocluster clumps G18.17,G18.21,G23.97N,G23.98,G23.44,G23.97S,G25.38,and G25.71.We found that the NH3cores are in good agreement with the 3.5 mm peak emission,but the NH_(3)is much more extended than the 3.5 mm emission structure.The SO distributions agree well with the 3.5 mm peaks for the evolved star formation stage,but we did not detect any SO emission in the four earliest star formation sources.C^(18)O is a poor tracer in conditions of the cold(■18 K)and dense(■10^(4)cm^(-3))cores,e.g.,the prestellar cores.We also found that the NH_(2)D cores are mainly located in the temperature range of 13.0-20.0 K,and the NH_(2)D lines may be strongly depleted above 20 K.

关 键 词：galaxies:star formation techniques:interferometric methods:observational 

分 类 号：O57[理学—粒子物理与原子核物理]