SiO emission from a huge, detached shell in IRC +10420 *
Observatorio Astronómico Nacional (IGN), Apdo. 1143, 28800 Alcalá de Henares, Spain e-mail: (bujarrabal,colomer,j.alcolea)@oan.es
2 IRAM, 300 rue de la Piscine, 38406 St Martin d'Hères, France e-mail: firstname.lastname@example.org
Corresponding author: A. Castro-Carrizo, email@example.com
Accepted: 6 February 2001
We present observations of the -1 thermal emission of SiO from the very luminous evolved star IRC +10420, performed with the Plateau de Bure interferometer. Our high-resolution maps show that the emission comes from a huge hollow shell, with a typical radius of ~1017 cm, that is expanding at ~35 km s-1. This surprising result is strengthened by model fitting of the flux distribution, that explains the observations assuming that the width of the shell is not larger than half its typical radius. The origin of this feature is discussed.
Key words: stars: individual: IRC +10420 / (stars:) circumstellar matter / stars: AGB y post-AGB / radio lines: stars / stars: mass-loss
© ESO, 2001