Naslov
Bipolar outflow on the asymptotic giant branch - the case of IRC+10011

Autori
Vinković, Dejan ; Bloecker, Thomas. ; Hofmann, Karl-Heinz ; Elitzur, Moshe ; Weigelt, Gert

Izvornik
Monthly Notices of the Royal Astronomical Society (0035-8711) 352 (2004), 3; 852-862

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
radiative transfer; stars: AGB and post-AGB; circumstellar matter; stars: imaging; stars: individual: IRC+10011; infrared: stars

Sažetak
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 Msolar 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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Informacijske i komunikacijske znanosti

POVEZANOST RADA