Peer-Reviewed Journal Details
Mandatory Fields
Lis, DC;Phillips, TG;Goldsmith, PF;Neufeld, DA;Herbst, E;Comito, C;Schilke, P;Muller, HSP;Bergin, EA;Gerin, M;Bell, TA;Emprechtinger, M;Black, JH;Blake, GA;Boulanger, F;Caux, E;Ceccarelli, C;Cernicharo, J;Coutens, A;Crockett, NR;Daniel, F;Dartois, E;De Luca, M;Dubernet, ML;Encrenaz, P;Falgarone, E;Geballe, TR;Godard, B;Giesen, TF;Goicoechea, JR;Gry, C;Gupta, H;Hennebelle, P;Hily-Blant, P;Kolos, R;Krelowski, J;Joblin, C;Johnstone, D;Kazmierczak, M;Lord, SD;Maret, S;Martin, PG;Martin-Pintado, J;Melnick, GJ;Menten, KM;Monje, R;Mookerjea, B;Morris, P;Murphy, JA;Ossenkopf, V;Pearson, JC;Perault, M;Persson, C;Plume, R;Qin, SL;Salez, M;Schlemmer, S;Schmidt, M;Sonnentrucker, P;Stutzki, J;Teyssier, D;Trappe, N;van der Tak, FFS;Vastel, C;Wang, S;Yorke, HW;Yu, S;Zmuidzinas, J;Boogert, A;Erickson, N;Karpov, A;Kooi, J;Maiwald, FW;Schieder, R;Zaal, P
2010
October
Astronomy and Astrophysics
Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C
Published
37 ()
Optional Fields
MOLECULAR CLOUDS COLOGNE DATABASE SUBMILLIMETER SPECTROSCOPY ABSORPTION ASTRONOMY AMMONIA OXYGEN VAPOR CDMS
521
We present Herschel/HIFI observations of the fundamental rotational transitions of ortho- and para-(H2O)-O-16 and (H2O)-O-18 in absorption towards Sagittarius B2(M) and W31C. The ortho/para ratio in water in the foreground clouds on the line of sight towards these bright continuum sources is generally consistent with the statistical high-temperature ratio of 3, within the observational uncertainties. However, somewhat unexpectedly, we derive a low ortho/para ratio of 2.35 +/- 0.35, corresponding to a spin temperature of similar to 27 K, towards Sagittarius B2(M) at velocities of the expanding molecular ring. Water molecules in this region appear to have formed with, or relaxed to, an ortho/para ratio close to the value corresponding to the local temperature of the gas and dust.
LES ULIS CEDEX A
0004-6361
10.1051/0004-6361/201015072
Grant Details