The circumstellar envelope of IRC+10216 from milli-arcsecond to arcmin scales

• Autor(a) principal: Leão, I. C.
• Data de Publicação: 2006
• Outros Autores: Laverny, P., Mékarnia, D., Medeiros, José Renan de, Vandame, B.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/jspui/handle/123456789/28886; https://doi.org/10.1051/0004-6361:20054577
• topic: Stars: AGB and post-AGB; Stars: variables: general; Stars: individual: IRC+10216; Stars: mass-loss; Stars: circumstellar matter; Techniques: high angular resolution

Aims. Analysis of the innermost regions of the carbon-rich star IRC+10216 and of the outer layers of its circumstellar envelope have been performed in order to constrain its mass-loss history. Methods. High dynamic range near infrared adaptive optics and high angular resolution deep V-band images of its circumstellar envelope collected with VLT/NACO and VLT/FORS1 instruments have been analyzed. Results. Maps of the sub-arcsecond structures, or clumps, in the innermost regions are derived from the near-infrared observations. The morphology of these clumps is found to strongly vary from J- to L-band. Their relative motion appears to be more complex than proposed in earlier works: they can be weakly accelerated, have a constant velocity, or even be motionless with respect to one another. From V-band imaging, a high spatial resolution map of the shell distribution in the outer layers of IRC+10216 is presented. Shells are well resolved up to a distance of about 90′′ to the core of the nebula and most of them appear to be composed of thinner elongated shells. Finally, by combining the NACO and FORS1 images, a global view, showing both the extended layers and the bipolar core of the nebula together with the real size of the inner clumps is presented. Conclusions. This study confirms the rather complex nature of the IRC+10216 circumstellar environment. In particular, the coexistence at different spatial scales of structures with very di fferent morphologies (clumps, bipolarity and almost spherical external layers) is very puzzling. This confirms that the formation of AGB winds is far more complex than usually assumed in current models.