DETECTION OF THE AMMONIUM ION IN SPACE

作者：Cernicharo J^*; Tercero B; Fuente A; Domenech J L; Cueto M; Carrasco E; Herrero V J; Tanarro I; Marcelino N; Roueff E; Gerin M; Pearson J

来源：Astrophysical Journal Letters, 2013, 771(1): L10.

DOI：10.1088/2041-8205/771/1/L10

• ISM: abundances
• ISM: individual objects (B1-bS)
• ISM: molecules
• line: identification molecular data

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(0)-0(0) line of the deuterated ammonium ion, NH3D+. 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 NH3D+ as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1(0)-0(0) transition of the ammonium ion, 262817 +/- 6MHz (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) x 10(12) cm(-2). Assuming a deuterium enhancement similar to that of NH2D, we derive N(NH4+) similar or equal to 2.6 x 10(13) cm(-2), i.e., an abundance for ammonium of a few 10(-11).

• 出版日期2013-7-1