First detection of NH3 (1(0) -> 0(0)) from a low mass cloud core - On the low ammonia abundance of the rho Oph A core

R Liseau, B Larsson, A Brandeker, P Bergman, P Bernath, J H Black, R Booth, V Buat, C Curry, P Encrenaz, E Falgarone, P Feldman, M Fich, H Floren, U Frisk, M Gerin, E Gregersen, J Harju, T Hasegawa, A HjalmarsonL Johansson, S Kwok, A Lecacheux, T Liljestrom, K Mattila, G Mitchell, L Nordh, M Olberg, G Olofsson, L Pagani, R Plume, I Ristorcelli, A Sandqvist, F von Scheele, G S Serra, N Tothill, K Volk, C Wilson

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Odin has successfully observed the molecular core rho Oph A in the 572.5 GHz rotational ground state line of ammonia, NH3 (J(K) = 1(0) --> 0(0)). The interpretation of this result makes use of complementary molecular line data obtained from the ground ((CO)-O-17 and CH3OH) as part of the Odin preparatory work. Comparison of these observations with theoretical model calculations of line excitation and transfer yields a quite ordinary abundance of methanol, X(CH3OH) = 3 X 10(-9). Unless NH3 is not entirely segregated from (CO)-O-17 and CH3OH, ammonia is found to be significantly underabundant with respect to typical dense core values, viz. X(NH3) = 8 X 10(-10).

Original languageEnglish
Pages (from-to)L73-L76
Number of pages4
JournalAstronomy & Astrophysics
Issue number3
Publication statusPublished - May 2003


  • ISM : individual objects : rho OphA
  • clouds
  • molecules
  • stars : formation

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