Dust-driven Winds Beyond Spherical Symmetry

摘要：

New 2D dynamical models for the winds of AGB stars are presented which include hydrodynamics with radiation pressure on dust,equilibrium chemistry,time-dependent dust formation theory,and coupled frequency-dependent Monte Carlo radiative transfer. The simulations reveal a much more complicated picture of the dust formation and wind acceleration as compared to 1D spherical wind models. Triggered by non-spherical pulsations or large-scale convective motions,dust forms event-like in the cooler regions above the stellar surface which are temporarily less illuminated,followed by the radial ejection of dust arcs and clumps. These simulations can possibly explain recent high angular resolution interferometric IR observations of red giants,which show an often non-symmetric and highly time-variable innermost dust formation and wind acceleration zone. The dependence of the mass-loss rates on stellar parameters is less threshold-like as used from 1D models,and therefore,it seems quite possible that the phenomenon of dust-driven winds may occur also in less evolved red giants.

关键词： hydrodynamics radiative transfer stars:late-type stars:winds stars:mass loss

作者: Peter Woitke

作者单位: UK Astronomy Technology Centre,Blackford Hill,EH9 3HJ Edinburgh,Scotland,UK;School of Physics & Astronomy,University of St Andrews,North Haugh,KY169SS St.Andrews,Scotland,UK

会议类型: 国际会议

会议名称: The 252th Symposium of the International Astronomical Union(国际天文学联合会第252届研讨会)

会议地点: 海南三亚

会议语种:英文

页码: 229-234

在线出版日期: 2008-04-06（万方平台首次上网日期，不代表论文的发表时间）