A rotating spiral structure in the innermost regions around IRC+10216

[摘要] ALMA interferometer is providing us molecular maps with unprecedent precision and sensitivity, Key processes in the ejection of matter and dust from these objects occur in their inner zones. We have obtained sub-arcsecond interferometric maps of rotational transitions of metal-bearing molecules towards the prototypical C-rich evolved star IRC+ 10216. While Al- bearing molecular emission presents a roughly spherical shell, the molecular emission from NaCl and KCl presents an elongation in the inner regions, with a central minimum. The presence of the observed features only in KCl and NaCl might be a direct result of their comparatively high dipole moment with respect to the Al-bearing species. The most plausible interpretation for the spatial distribution of the salts is a spiral with a NaCl mass of 0.08 Mowith an inner radius of 27 AU. The gas kinematics suggests that it is slowly expanding and rotating. Alternative gas distributions which could result in the presence of the elongation are also explored.

[发布机构] Group of Molecular Astrophysics. ICMM, CSIC, C/ Sor Juana Inés de la Cruz 3, Cantoblanco, Madrid; 28049, Spain^1;Centro de Astrobiologìa, INTA-CSIC, Villanueva de la Cañada, Madrid; E-28691, Spain^2;Institut de Radioastronomie Millimétrique, 300 rue de la la Piscine, St.-Martin d'Heères; F-38406, France^3;INAF, Istituto di Radioastronomia, via P. Gobetti 101, Bologna; 40129, Italy^4;Grupo de Espectroscopìa Molecular, Edificio Quifima, Laboratorios de Espectroscopìa y Bioespectroscopìa, Unidad Asociada CSIC, Parque Cientìfico Uva, Universidad de Valladolid, Paseo de Belén 5, Valladolid; E-47011, Spain^5;Universidad de Murcia, Faculdad de Quìmica, Dpto. de Quìmica-Fìsica, Campus Espinardo, Murcia; E-30100, Spain^6;LOMC-UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP. 1123, Le Havre Cedex; 76063, France^7;Department of Optics and Spectroscopy, Tomsk State University, 36 Lenin av., Tomsk; 634050, Russia^8;LERMA, Observatoire de Paris, PSL Research University, CNRS, UMR 8112, Paris; F-75014, France^9

[效力级别] 天文学 [学科分类] 天文学(综合)

[关键词] Evolved stars;Gas distribution;Metal bearings;Molecular emissions;Molecular maps;Rotational transition;Spherical shell;Spiral structures