Open AccessBipolar outflow on the asymptotic giant branch – the case of IRC+10011
Author(s) -
Vinković Dejan,
Blöcker Thomas,
Hofmann KarlHeinz,
Elitzur Moshe,
Weigelt Gerd
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07972.x
Subject(s) - physics , asymptotic giant branch , bipolar outflow , planetary nebula , radiative transfer , outflow , astrophysics , circular symmetry , astronomy , bipolar nebula , stars , star formation , protoplanetary nebula , meteorology , quantum mechanics
Near‐infrared imaging of the asymptotic giant branch (AGB) star IRC+10011 (= CIT3) reveals the presence of a bipolar structure within the central ∼0.1 arcsec of a spherical dusty wind. We show that the image asymmetries originate from ∼10 −4 M ⊙ of swept‐up wind material in an elongated cocoon whose expansion is driven by bipolar jets. We perform detailed 2D radiative transfer calculations with the cocoon modelled as two cones extending to ∼1100 au within an opening angle of ∼30°, embedded in a wind with the standard r −2 density profile. The cocoon expansion started ≲200 yr ago, while the total lifetime of the circumstellar shell is ∼5500 yr. Similar bipolar expansion, at various stages of evolution, has been recently observed in a number of other AGB stars, culminating in jet breakout from the confining spherical wind. The bipolar outflow is triggered at a late stage in the evolution of AGB winds, and IRC+10011 provides its earliest example thus far. These new developments enable us to identify the first instance of symmetry breaking in the evolution from AGB to planetary nebula.