大质量恒星形成区中H2O+/H2O比率的变化
星系天体物理
2015-05-19 v1
摘要
赫歇尔空间天文台的早期结果显示，水阳离子H2O+是星际介质中一种丰富的成分。本文利用赫歇尔空间天文台，对一批大质量恒星形成区在1113.3和1115.2 GHz处的新H2O和H2O+谱线观测进行了介绍，以观测研究H2O与H2O+之间的关系。十个源中有九个在不同环境中显示出H2O+的吸收：围绕正在形成和新形成的大质量恒星的分子团块、与大质量原恒星相关的明亮高速外流，以及视线方向上无关的低密度云。每个速度分量的H2O+柱密度在10^12到几个10^13 cm^-2范围内。最高的N(H2O+)柱密度出现在源的外流中。H2O+/H2O比率在0.01到几个的范围内，并发现不同观测环境之间存在显著差异，大质量（原）星团包层中的比率（0.01-0.1）远低于外流和弥散云中的比率。值得注意的是，即使在H2O发射探测到的源成分中，H2O+仍以吸收形式出现。
引用
@article{arxiv.1007.4370,
title = {Variations in H2O+/H2O ratios toward massive star-forming regions},
author = {F. Wyrowski and F. van der Tak and F. Herpin and A. Baudry and S. Bontemps and L. Chavarria and W. Frieswijk and T. Jacq and M. Marseille and R. Shipman and E. F van Dishoeck and A. O. Benz and P. Caselli and M. R. Hogerheijde and D. Johnstone and R. Liseau and R. Bachiller and M. Benedettini and E. Bergin and P. Bjerkeli and G. Blake and J. Braine and S. Bruderer and J. Cernicharo and C. Codella and F. Daniel and A. M. di Giorgio and C. Dominik and S. D. Doty and P. Encrenaz and M. Fich and A. Fuente and T. Giannini and J. R. Goicoechea and Th. de Graauw and F. Helmich and G. J. Herczeg and J. K. Jørgensen and L. E. Kristensen and B. Larsson and D. Lis and C. McCoey and G. Melnick and B. Nisini and M. Olberg and B. Parise and J. C. Pearson and R. Plume and C. Risacher and J. Santiago and P. Saraceno and M. Tafalla and T. A. van Kempen and R. Visser and S. Wampfler and U. A. Yıldız and J. H. Black and E. Falgarone and M. Gerin and P. Roelfsema and P. Dieleman and D. Beintema and A. De Jonge and N. Whyborn and J. Stutzki and V. Ossenkopf},
journal= {arXiv preprint arXiv:1007.4370},
year = {2015}
}
备注
5 pages, 4 figures, accepted for publication as a letter in the A&A Herschel-HIFI special issue