Detection of HCO<sup><nobr>+</nobr></sup> towards Cygnus OB2 No. 12期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

Detection of HCO⁺ towards Cygnus OB2 No. 12

Authors:	Flavio Scappini Cesare Cecchi-Pestellini Claudio Codella Alexander Dalgarno

Affiliation:	Istituto di Spettroscopia Molecolare del C. N. R., Via P. Gobetti 101, 40129 Bologna, Italy;Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA;Dipartimento di Astronomia e Scienza dello Spazio, Universitàdi Firenze, Largo E.Fermi 5, 50125 Firenze, Italy;Istituto di Fisica dello Spazio Interplanetario del C. N. R., Via Fosso del Cavaliere 100, 00133 Roma, Italy

Abstract:	HCO⁺ has been detected for the first time towards the star Cygnus OB2 No. 12 through emission of the 1–0 rotational transition at 89 GHz. The CO( J =2?1) transition has also been observed. The observations are consistent with a model of dense regions embedded in a low-density clump gas. If actually present, the dense component would have an aggregate size L 1300 au, in agreement with estimates of small-scale density fluctuations observed along diffuse lines of sight.

Keywords:	stars: individual: Cygnus OB2 No 12 ISM: abundances ISM: clouds ISM: molecules