DETECTION OF THE AMMONIUM ION IN SPACE
- Deparment of Astrophysics, CAB, INTA-CSIC, Crta Torrejon-Ajalvir Km 4, E-28850 Torrejon de Ardoz, Madrid (Spain)
- Observatorio Astronomico Nacional, Apdo. 112, E-28803 Alcala de Henares (Spain)
- Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006 Madrid (Spain)
- NRAO, 520 Edgemont Road, Charlottesville, VA 22902 (United States)
- Luth, Observatoire de Paris, CNRS UMR8102, Place J. Janssen F-92190 Meudon (France)
- LERMA, Observatoire de Paris, CNRS UMR8112 and Ecole Normale Superieure, 61 Avenue de lObservatoire, F-75014 Paris (France)
We report on the detection of a narrow feature at 262816.73 MHz toward Orion and the cold prestellar core B1-bS which we attribute to the 1{sub 0}-0{sub 0} line of the deuterated ammonium ion, NH{sub 3}D{sup +}. The observations were performed with the IRAM 30 m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved, indicating a very low value for the electric quadrupolar coupling constant of nitrogen which is expected for NH{sub 3}D{sup +} as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1{sub 0}-0{sub 0} transition of the ammonium ion, 262817 {+-} 6 MHz (3{sigma}), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is (1.1 {+-} 0.2) Multiplication-Sign 10{sup 12} cm{sup -2}. Assuming a deuterium enhancement similar to that of NH{sub 2}D, we derive N(NH{sub 4}{sup +}) {approx_equal} 2.6 Multiplication-Sign 10{sup 13} cm{sup -2}, i.e., an abundance for ammonium of a few 10{sup -11}.
- OSTI ID:
- 22118716
- Journal Information:
- Astrophysical Journal Letters, Vol. 771, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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