Characteristics of convection and overshooting in RGB and AGB stars

	Characteristics of convection and overshooting in RGB and AGB stars
	Lai XJ(赖祥军)1,2,3 ; Li Y(李焱)1,2
刊名	RESEARCH IN ASTRONOMY AND ASTROPHYSICS
	2011-10
卷号	11 期号:10 页码:1143-1157
关键词	stars: RGB and AGB convection of stars turbulent convection model: convective overshooting
ISSN号	1674-4527
通讯作者	Lai, XJ (reprint author), Chinese Acad Sci, Yunnan Observ, Natl Astron Observ, Kunming 650011, Peoples R China.
产权排序	第一完成单位
英文摘要	Based on the turbulent convection model (TCM) of Li & Yang, we have studied the characteristics of turbulent convection in the envelopes of 2 and 5M(circle dot) stars at the red giant branch and asymptotic giant branch phases. The TCM has been successfully applied over the entire convective envelopes, including the convective unstable zone and the overshooting regions. We find that the convective motions become progressively stronger when the stellar models are located farther up along the Hayashi line. In the convective unstable zone, we find that the turbulent correlations are proportional to functions of a common factor (del - del(ad))(T) over bar, which explains similar distributions in those correlations. For the TCM we find that if the obtained stellar temperature structure is close to that of the mixing length theory (MLT), the convective motion will have a much larger velocity and thus be more violent. However, if the turbulent velocity is adjusted to be close to that of the MLT, the superadiabatic convection zone would be much more extended inward, which would lead to a lower effective temperature of the stellar model. For the overshooting distance, we find that the e-folding lengths of the turbulent kinetic energy k in both the top and bottom overshooting regions decrease as the stellar model is progressively located farther up along the Hayashi line, but both the extents of the decrease are not obvious. The overshooting distances of the turbulent correlation (u(T)'T') over bar are almost the same for the different stellar models with the same set of TCM parameters. For the decay modes of the kinetic energy k, we find that they are very similar for different stellar models based on the same set of TCM parameters, and there is a nearly linear relationship between lg k and In P for different stellar models. When C-s or alpha increases while the other parameters are fixed, the obtained linearly decaying distance will become longer.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	STELLAR TURBULENT CONVECTION ; REYNOLDS STRESS APPROACH ; HORIZONTAL-BRANCH STARS ; MIXING-LENGTH THEORY ; RED GIANT BRANCH ; SOLAR MODELS ; LOW-MASS ; INTERMEDIATE-MASS ; EVOLUTION ; NUCLEOSYNTHESIS
收录类别	SCI
原文出处	http://iopscience.iop.org/article/10.1088/1674-4527/11/10/003/meta
语种	英语
WOS记录号	WOS:000296127800003
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/5206]
专题	云南天文台_恒星物理研究组云南天文台_中国科学院天体结构与演化重点实验室
作者单位	1.National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011, China 2.Key Laboratory for the Structure and Evolution of Celestial Objects, Chinse Academy of Sciences, Kunming 650011, China 3.Graduate University of Chinese Academy of Sciences, Beijing 100049, China
推荐引用方式 GB/T 7714	Lai XJ,Li Y. Characteristics of convection and overshooting in RGB and AGB stars[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2011,11(10):1143-1157.
APA	Lai XJ,&Li Y.(2011).Characteristics of convection and overshooting in RGB and AGB stars.RESEARCH IN ASTRONOMY AND ASTROPHYSICS,11(10),1143-1157.
MLA	Lai XJ,et al."Characteristics of convection and overshooting in RGB and AGB stars".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 11.10(2011):1143-1157.