Tentative detection of the nitrosylium ion in space
- Departamento de Astrofísica, Centro de Astrobiología, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain)
- Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS, Université Lille 1, F-59655 Villeneuve d'Ascq Cedex (France)
- Institute of Radio Astronomy, National Academy of Sciences of Ukraine, Krasnoznamennaya ul. 4, Kharkov 61002 (Ukraine)
- Observatorio Astronómico Nacional, Apdo. 112, E-28803 Alcalá de Henares (Spain)
- LERMA, Observatoire de Paris, CNRS UMR 8112. Place J. Janssen, F-92190 Meudon (France)
- LERMA, Observatoire de Paris, CNRS UMR8112 and Ecole Normale Superieure, 61 Avenue de l'Observatoire, F-75014 Paris (France)
- Instituto de Radio Astronomía Milimétrica (IRAM), Avenida Divina Pastora 7, Local 20, E-18012 Granada (Spain)
- NRAO, 520 Edgemont Road, Charlottesville, VA 22902 (United States)
- UJF-Grenoble/CNRS-INSU, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, F-38041 Grenoble (France)
We report the tentative detection in space of the nitrosylium ion, NO{sup +}. The observations were performed toward the cold dense core Barnard 1-b. The identification of the NO{sup +} J = 2-1 line is supported by new laboratory measurements of NO{sup +} rotational lines up to the J = 8-7 transition (953207.189 MHz), which leads to an improved set of molecular constants: B {sub 0} = 59597.1379(62) MHz, D {sub 0} = 169.428(65) kHz, and eQq {sub 0}(N) = –6.72(15) MHz. The profile of the feature assigned to NO{sup +} exhibits two velocity components at 6.5 and 7.5 km s{sup –1}, with column densities of 1.5 × 10{sup 12} and 6.5 × 10{sup 11} cm{sup –2}, respectively. New observations of NO and HNO, also reported here, allow us to estimate the following abundance ratios: X(NO)/X(NO{sup +}) ≅ 511, and X(HNO)/X(NO{sup +}) ≅ 1. This latter value provides important constraints on the formation and destruction processes of HNO. The chemistry of NO{sup +} and other related nitrogen-bearing species is investigated by the means of a time-dependent gas phase model which includes an updated chemical network according to recent experimental studies. The predicted abundance for NO{sup +} and NO is found to be consistent with the observations. However, that of HNO relative to NO is too high. No satisfactory chemical paths have been found to explain the observed low abundance of HNO. HSCN and HNCS are also reported here with an abundance ratio of ≅ 1. Finally, we have searched for NNO, NO{sub 2}, HNNO{sup +}, and NNOH{sup +}, but only upper limits have been obtained for their column density, except for the latter for which we report a tentative 3σ detection.
- OSTI ID:
- 22370322
- Journal Information:
- Astrophysical Journal, Vol. 795, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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