早期阶段大质量团块中的HCN、HNC、HCO^(+)和CN化学性质研究  

Chemical Properties of HCN,HNC,HCO^(+)and CN in the Early Stages of High-mass Clumps

作　　者：李宏杰 何玉新[2,3,4] 周建军 加尔肯·叶生别克[2,3,4] 周冬冬 LI Hong-jie;HE Yu-xin;ZHOU Jian-jun;ESIMBEK Jarken;ZHOU Dong-dong(College of Physical Science and Technology,Xinjiang University,Urumqi 830046;Xinjiang Astronomical Observatories,Chinese Academy of Sciences,Urumqi 830011;Key Laboratory of Radio Astronomy,Chinese Academy of Sciences,Nanjing 210023;Xinjiang Key Laboratory of Radio Astrophysics,Urumqi 830011)

机构地区：[1]新疆大学物理科学与技术学院,乌鲁木齐830046 [2]中国科学院新疆天文台,乌鲁木齐830011 [3]中国科学院射电天文重点实验室,南京210023 [4]新疆射电天体物理重点实验室,乌鲁木齐830011

出　　处：《天文学报》2024年第4期113-134,共22页Acta Astronomica Sinica

基　　金：中国科学院西部之光-西部青年学者项目(2020-XBQNXZ-017、2021-XBQNXZ-028);新疆维吾尔自治区重点实验室开放课题(2023D04033);新疆维吾尔自治区区域协同创新专项(上海合作组织科技伙伴计划及国际科技合作计划,项目编号:2022E01050);新疆维吾尔自治区自然科学基金项目(2022D01A359)资助。

摘　　要：选择67个相对孤立的大质量恒星形成团块,使用4种分子谱线(HCN(1-0)、HNC(1-0)、HCO^(+)(1-0)和CN(1-0),括号中的1-0代表分子从转动能级1跃迁到转动能级0)和红外波段数据,研究它们的整体化学性质.通过对源的积分强度、柱密度、分子丰度和丰度比在不同演化阶段的统计,发现大质量恒星形成团块CN(1-0)、HCO^(+)(1-0)、HCN(1-0)和HNC(1-0)的积分强度和柱密度中值随着演化阶段的增加都呈现增加趋势,这与理论预期相符.然而单一分子进行的柱密度和丰度统计结果存在较大的误差,用以示踪的演化阶段有很大的局限性.I(CN)/I(HNC)、I(CN)/I(HCN)和I(HCN)/I(HCO^(+))的积分强度比随演化阶段递增(I代表分子的积分强度),是潜在的用来示踪大质量恒星形成团块演化的探针;N(CN)/N(H2)、N(HNC)/N(H2)和N(HCN)/N(HCO^(+))的中值随演化阶段单调递增(N代表分子的柱密度),有希望作为示踪大质量恒星演化的化学探针.需要注意的是由于研究工作观测数据的限制,不能获得各分子的光学厚度,受光学厚度影响得不到可靠的柱密度,从而得不到可靠的丰度,最终影响对丰度比化学时钟的检验.We selected 67 relatively isolated massive star-forming clumps and studied their overall chemical properties using four molecular spectral lines(HCN(1-0),HNC(1-0),HCO^(+)(1-0),and CN(1-0),where the numbers in parentheses represent the transition from rotational energy level 1 to rotational energy level 0)and infrared band data.Based on the statistics of the source’s integral intensity,column density,molecular abundance and abundance ratio at different evolutionary stages,we found that the median values of the integral intensity and column density of the massive star forming clumps CN(1-0),HCO^(+)(1-0),HCN(1-0)and HNC(1-0)all showed an increasing trend with the increase of the evolutionary stage,which is consistent with the theoretical expectation.However,the statistical results of column density and abundance based on a single molecule have large errors.The stage of evolution used to trace is very limited.The integral intensity ratio of I(CN)/I(HNC),I(CN)/I(HCN)and I(HCN)/I(HCO^(+))increases with the evolution stage(I represents the integrated intensity of the molecule),which is a potential probe to trace the evolution of massive star forming clumps.The median values of N(CN)/N(H2),N(HNC)/N(H2)and N(HCN)/N(HCO^(+))increase monotonically with the evolution stage(N represents the column density of the molecule),which is promising as a chemical probe to trace the evolution of massive stars.It should be noted that due to the limitations of the observational data in this study,optical depths of individual molecules cannot be obtained.As a result,reliable column densities and abundances cannot be determined,which ultimately affects the testing of abundance ratio chemical clocks.

关 键 词：星际介质:分子 星际介质:丰度 恒星:形成 星际介质:谱线与谱带 

分 类 号：P154[天文地球—天文学]