Turbulent convection and pulsational stability of variable stars. II. Oscillations of RR Lyrae and horizontal branch red variable stars

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	Turbulent convection and pulsational stability of variable stars. II. Oscillations of RR Lyrae and horizontal branch red variable stars
	Xiong, DR; Cheng, QL ; Deng, L
刊名	ASTROPHYSICAL JOURNAL
	1998-06-10
卷号	500 期号:1 页码:449-465
关键词	convection stars : horizontal-branch stars : oscillations stars : variables : other (RR Lyrae)
ISSN号	0004-637X
英文摘要	Using a nonlocal time-dependent theory of convection, we have calculated the linear nonadiabatic oscillations of horizontal branch (HB) stars, carefully treating both the dynamic and thermodynamic coupling between convection and oscillations. Turbulent pressure and turbulent viscosity have been included consistently in our equations of nonadiabatic pulsation. When the coupling between convection and oscillations is ignored, for all models with T-e less than or equal to 7350 K, the fundamental through the second overtone are pulsationally unstable, while for T-e less than or equal to 6200 K all the models are unstable up to (at least) the 9th overtone. When the coupling between convection and oscillations is included, the RR Lyrae instability strip is very well predicted. Within the strip, most models are pulsationally unstable only for the fundamental and the first few low-order overtones. The turbulent viscosity is an important damping mechanism. Being exclusively distinct from the luminous red variables (long-period variables), the HE stars to the right of the RR strip are pulsationally stable for the fundamental and low-order overtones, but become unstable for some of the high-order overtones. This may provide a valuable clue to the short-period, low-amplitude red variables found outside the red edge of the RR strip on the H-R diagram of globular clusters. We also present a new radiation-modulated excitation mechanism functioning in a zone of radiation flux gradient. The effects of nonlocal convection and the dynamic coupling between convection and oscillations are discussed. The spatial oscillations of the thermal variables in the pulsational calculations have been effectively suppressed.
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 ENVELOPES ; GLOBULAR-CLUSTER ; EQUATION ; STATE ; EDGE
收录类别	SCI
语种	英语
WOS记录号	WOS:000074273300038
公开日期	2015-04-20
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/11181]
专题	紫金山天文台_院士文集_熊大闰
作者单位	1.Acad Sinica, Purple Mt Observ, Nanjing 210008, Peoples R China 2.Acad Sinica, Beijing Astron Observ, Beijing 100080, Peoples R China
推荐引用方式 GB/T 7714	Xiong, DR,Cheng, QL,Deng, L. Turbulent convection and pulsational stability of variable stars. II. Oscillations of RR Lyrae and horizontal branch red variable stars[J]. ASTROPHYSICAL JOURNAL,1998,500(1):449-465.
APA	Xiong, DR,Cheng, QL,&Deng, L.(1998).Turbulent convection and pulsational stability of variable stars. II. Oscillations of RR Lyrae and horizontal branch red variable stars.ASTROPHYSICAL JOURNAL,500(1),449-465.
MLA	Xiong, DR,et al."Turbulent convection and pulsational stability of variable stars. II. Oscillations of RR Lyrae and horizontal branch red variable stars".ASTROPHYSICAL JOURNAL 500.1(1998):449-465.