Astronomy & Astrophysics manuscript no. 0587 c ESO 2018 October 31, 2018 Chemical modeling of L183 (= L134N) : an estimate of the ortho/para H2 ratio L. Pagani1, C. Vastel2, E. Hugo3, V. Kokoouline4, Chris H. Greene5, A. Bacmann6, E. Bayet7, C. Ceccarelli6, R. Peng8, and S. Schlemmer3 1 LERMA & UMR8112 du CNRS, Observatoire de Paris, 61, Av. de l’Observatoire, 75014 Paris, France e-mail:
[email protected] 2 CESR, 9 avenue du colonel Roche, BP44348, Toulouse Cedex 4, France e-mail:
[email protected] 3 I. Physikalisches Institut, Universit¨at zu K¨oln, Z¨ulpicher Strasse 77, 50937 K¨oln, Germany e-mail:
[email protected],
[email protected] 4 Department of Physics, University of Central Florida, Orlando, FL-32816, USA e-mail:
[email protected] 5 Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309-0440, USA e-mail:
[email protected] 6 Laboratoire d’Astrophysique de Grenoble, Universit´eJoseph Fourier, UMR5571 du CNRS, 414 rue de la Piscine, 38041 Grenoble Cedex 09, France e-mail:
[email protected],
[email protected] 7 Department of physics and astronomy, University College London, Gower street, London WC1E 6BT, UK e-mail:
[email protected] 8 Caltech Submillimeter Observatory, 111 Nowelo Street, Hilo, HI 96720, USA e-mail:
[email protected] Received 15/07/2008; accepted October 31, 2018 ABSTRACT + Context. The high degree of deuteration observed in some prestellar cores depends on the ortho-to-para H2 ratio through the H3 fractionation. Aims.