Early phases of star formation: testing chemical tools

IF 1.8 4区 物理与天体物理 Q3 ASTRONOMY & ASTROPHYSICS Research in Astronomy and Astrophysics Pub Date : 2023-10-17 DOI:10.1088/1674-4527/ad0429
Sergio Paron
{"title":"Early phases of star formation: testing chemical tools","authors":"Sergio Paron","doi":"10.1088/1674-4527/ad0429","DOIUrl":null,"url":null,"abstract":"Abstract The star forming processes strongly influence the ISM chemistry. 
Nowadays, there are available many high-quality databases at millimeter wavelengths. Using them, it is possible to carry out studies that review and deepen previous results. If these studies involve large samples of sources, it is preferred to use {\\bf direct} tools to study the molecular gas.
With the aim of testing these tools such as the use of the HCN/HNC ratio as a thermometer, and the use of H$^{13}$CO$^{+}$, HC$_{3}$N, N$_{2}$H$^{+}$, and C$_{2}$H as ``chemical clocks'', we present a molecular line study towards 55 sources representing {\\bf massive young stellar objects (MYSOs)} at different evolutive stages: infrared dark clouds (IRDCs), high-mass protostellar objects (HMPOs), hot molecular cores (HMCs) and {\\bf ultracompact \\hii~regions (UC\\hii)}.
We found that the use of HCN/HNC ratio as an universal thermometer in the ISM should be taken with care because the HCN optical depth is a big issue that can affect the method. Hence, this tool should be used only after a careful analysis of the HCN spectrum, checking that no line, neither the main nor the hyperfine ones, present absorption features.
We point out that the analysis of the emission of H$^{13}$CO$^{+}$, HC$_{3}$N, N$_{2}$H$^{+}$, and C$_{2}$H could be useful to trace and distinguish regions among IRDCs, HMPOs and HMCs. 
The molecular line widths of these four species increase from the IRDC to the HMC stage, which can be a consequence of the gas dynamics related to the star-forming processes taking place in the molecular clumps. 
Our results do not only contribute with more statistics regarding to probe such chemical tools, useful to obtain information in large samples of sources, but also complement previous works through the analysis on other types of sources.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"25 1","pages":"0"},"PeriodicalIF":1.8000,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Research in Astronomy and Astrophysics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1088/1674-4527/ad0429","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0

Abstract

Abstract The star forming processes strongly influence the ISM chemistry. 
Nowadays, there are available many high-quality databases at millimeter wavelengths. Using them, it is possible to carry out studies that review and deepen previous results. If these studies involve large samples of sources, it is preferred to use {\bf direct} tools to study the molecular gas.
With the aim of testing these tools such as the use of the HCN/HNC ratio as a thermometer, and the use of H$^{13}$CO$^{+}$, HC$_{3}$N, N$_{2}$H$^{+}$, and C$_{2}$H as ``chemical clocks'', we present a molecular line study towards 55 sources representing {\bf massive young stellar objects (MYSOs)} at different evolutive stages: infrared dark clouds (IRDCs), high-mass protostellar objects (HMPOs), hot molecular cores (HMCs) and {\bf ultracompact \hii~regions (UC\hii)}.
We found that the use of HCN/HNC ratio as an universal thermometer in the ISM should be taken with care because the HCN optical depth is a big issue that can affect the method. Hence, this tool should be used only after a careful analysis of the HCN spectrum, checking that no line, neither the main nor the hyperfine ones, present absorption features.
We point out that the analysis of the emission of H$^{13}$CO$^{+}$, HC$_{3}$N, N$_{2}$H$^{+}$, and C$_{2}$H could be useful to trace and distinguish regions among IRDCs, HMPOs and HMCs. 
The molecular line widths of these four species increase from the IRDC to the HMC stage, which can be a consequence of the gas dynamics related to the star-forming processes taking place in the molecular clumps. 
Our results do not only contribute with more statistics regarding to probe such chemical tools, useful to obtain information in large samples of sources, but also complement previous works through the analysis on other types of sources.
查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
恒星形成的早期阶段:测试化学工具
恒星形成过程对ISM化学有很大影响。如今,有许多高质量的毫米波数据库可用。利用它们,可以进行研究,审查和深化以前的结果。如果这些研究涉及大量的源样本,最好使用{\bf直接}工具来研究分子气体。 为了测试这些工具,如使用HCN/HNC比率作为温度计,使用H$^{13}$CO$^{+}$, HC$ $ {3}$N, N$ $ {2}$H$^{+}$和C$ $ {2}$H作为“化学时钟”,我们提出了代表{\bf大质量年轻恒星天体(MYSOs)}的55个源的分子线研究。红外暗云(IRDCs)、高质量原恒星天体(HMPOs)、热分子核(HMCs)和{\bf超压缩\hii~区域(UC\hii)}.我们发现,在ISM中使用HCN/HNC比值作为通用温度计应该谨慎,因为HCN光学深度是影响方法的一个大问题。因此,只有对HCN光谱进行仔细的分析,检查主谱线和超细谱线都没有吸收特征。 。我们指出,对H$^{13}$CO$^{+}$、HC$ $ {3}$N、N$ $ {2}$H$ $^{+}$和C$ $ {2}$H的发射分析可以用来追踪和区分irdc、HMPOs和hmc之间的区域。从IRDC到HMC阶段,这四种物质的分子线宽度增加,这可能是与分子团块中发生的恒星形成过程相关的气体动力学的结果。我们的结果不仅有助于提供更多关于探测这类化学工具的统计数据,有助于在大量来源样本中获取信息,而且还通过对其他类型来源的分析补充了以前的工作。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 去求助
来源期刊
Research in Astronomy and Astrophysics
Research in Astronomy and Astrophysics 地学天文-天文与天体物理
CiteScore
3.20
自引率
16.70%
发文量
2599
审稿时长
6.0 months
期刊介绍: Research in Astronomy and Astrophysics (RAA) is an international journal publishing original research papers and reviews across all branches of astronomy and astrophysics, with a particular interest in the following topics: -large-scale structure of universe formation and evolution of galaxies- high-energy and cataclysmic processes in astrophysics- formation and evolution of stars- astrogeodynamics- solar magnetic activity and heliogeospace environments- dynamics of celestial bodies in the solar system and artificial bodies- space observation and exploration- new astronomical techniques and methods
期刊最新文献
Comparison of NH3 and 12CO, 13CO, C18O Molecular Lines in the Aquila Rift Cloud Complex SFNet: Stellar Feature Network with CWT for Stellar Spectra Recognition A Study of the Comets with Large Perihelion Distances C/2019 L3 (ATLAS) and C/2019 O3 (Palomar) Understanding the Impact of H2 Diffusion Energy on the Formation Efficiency of H2 on the Interstellar Dust Grain Surface Leveraging the Empirical Wavelet Transform in Combination with Convolutional LSTM Neural Networks to Enhance the Accuracy of Polar Motion Prediction
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1