000002240 001__ 2240
000002240 005__ 20160706143019.0
000002240 0247_ $$2DOI$$a10.1051/0004-6361/201117360
000002240 037__ $$aASTROimport-397
000002240 100__ $$aDecin, L.
000002240 245__ $$aDiscovery of multiple dust shells beyond 1 arcmin in the circumstellar envelope of IRC +10216 using Herschel/PACS
000002240 260__ $$c2011
000002240 520__ $$aWe present new Herschel/PACS images at 70, 100, and 160 µm of the well-known, nearby, carbon-rich asymptotic giant branch star IRC+10216 revealing multiple dust shells in its circumstellar envelope. For the first time, dust shells (or arcs) are detected until 320''. The almost spherical shells are non-concentric and have an angular extent between ~40° and ~200°. The shells have a typical width of 5''-8'', and the shell separation varies in the range of ~10''-35'', corresponding to ~500 -1 700 yr. Local density variations within one arc are visible. The shell/intershell density contrast is typically ~4, and the arcs contain some 50% more dust mass than the smooth envelope. The observed (nested) arcs record the mass-loss history over the past 16 000 yr, but Rayleigh-Taylor and Kelvin-Helmholtz instabilities in the turbulent astropause and astrosheath will erase any signature of the mass-loss history for at least the first 200 000 yr of mass loss. Accounting for the bowshock structure, the envelope mass around IRC+10216 contains >2 M? of gas and dust mass. It is argued that the origin of the shells is related to non-isotropic mass-loss events and clumpy dust formation. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
000002240 700__ $$aRoyer, P.
000002240 700__ $$aCox, N. L. J.
000002240 700__ $$aVandenbussche, B.
000002240 700__ $$aOttensamer, R.
000002240 700__ $$aBlommaert, J. A. D. L.
000002240 700__ $$aGroenewegen, M. A. T.
000002240 700__ $$aBarlow, M. J.
000002240 700__ $$aLim, T.
000002240 700__ $$aKerschbaum, F.
000002240 700__ $$aPosch, T.
000002240 700__ $$aWaelkens, C.
000002240 773__ $$cA1$$pAstronomy and Astrophysics$$v534$$y2011
000002240 85642 $$ahttp://esoads.eso.org/abs/2011A%26A...534A...1D
000002240 905__ $$apublished in
000002240 980__ $$aREFERD