Deathzones and exponents:A different approach to incorporating mass loss in stellar evolution calculations

摘要：

Observations tend to select mass loss rates near the critical rate,(M)crit = M(L)/L. There are two reasons for this. In some situations,such as near the tip of the AGB,the mass loss rate is very sensitive to stellar parameters. In this case,stars with (M)(＜)(M)crit have dustfree,hard-to-measure mass loss rates while stars with (M)(>) (M)crit do not survive very long and thus make up a small fraction of any sample. Selection effects dominate the fitting of empirical formulae; observations of mass loss rates tell us more about which stars are losing mass than about how a star loses mass. In other situations,such as for some of the stars along the RGB,a steady state situation occurs where the loss of mass leads to a decrease in mass loss rate while the evolutionary changes lead to an increase; the result is a steady state with (M) = (M)crit To determine the envelope mass and composition at the end of a phase of intensive mass loss requires stellar evolution models capable of responding on a time scale ～ tKH and thus,a new generation of stellar modeling codes.

关键词： Stars:mass loss stars:evolution

作者: Lee Anne Willson

作者单位: Department of Physics and Astronomy,Iowa State University,Ames,IA 50010,USA

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: 189-196

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）