发展了一种简单的双温模型用于研究黑子对活动星的视星等、颜色和视Li丰度的影响.在适当的黑子覆盖因子下,恒星黑子能产生可观的活动星的视星等(V星等约±0.2星等)、颜色(B-V颜色约-0.1星等)和Li I λ6708 (?)谱线等值宽度(约-0.2-0...发展了一种简单的双温模型用于研究黑子对活动星的视星等、颜色和视Li丰度的影响.在适当的黑子覆盖因子下,恒星黑子能产生可观的活动星的视星等(V星等约±0.2星等)、颜色(B-V颜色约-0.1星等)和Li I λ6708 (?)谱线等值宽度(约-0.2-0.3 dex)的变化.与非活动的正常恒星相比,表面被黑子覆盖的活动星有更蓝的B-V颜色,它们的Li I λ6708 (?)谱线的等值宽度也变窄.根据观测到的活动星黑子引起的光变变幅,估计视圆面黑子覆盖率的变化范围△Fs从百分之几到约0.2.视圆面黑子覆盖率不太可能超过0.3.展开更多
Revised Hipparcos data were released by van Leeuwen in 2007.In this article revised Hipparcos trigo-nometrical parallaxes are used to derive a period-luminosity zero-point in the optical V band.Adopting a fixed slope ...Revised Hipparcos data were released by van Leeuwen in 2007.In this article revised Hipparcos trigo-nometrical parallaxes are used to derive a period-luminosity zero-point in the optical V band.Adopting a fixed slope of -2.81 from the LMC,a zero-point value of ρ= -1.37±0.07 is derived based on the method by Feast and Catchpole(1997).This value yields an LMC distance modulus of 18.64 mag,which makes a minor change in H0 expected from Feast and Catchpole's result in 1997.展开更多
文摘发展了一种简单的双温模型用于研究黑子对活动星的视星等、颜色和视Li丰度的影响.在适当的黑子覆盖因子下,恒星黑子能产生可观的活动星的视星等(V星等约±0.2星等)、颜色(B-V颜色约-0.1星等)和Li I λ6708 (?)谱线等值宽度(约-0.2-0.3 dex)的变化.与非活动的正常恒星相比,表面被黑子覆盖的活动星有更蓝的B-V颜色,它们的Li I λ6708 (?)谱线的等值宽度也变窄.根据观测到的活动星黑子引起的光变变幅,估计视圆面黑子覆盖率的变化范围△Fs从百分之几到约0.2.视圆面黑子覆盖率不太可能超过0.3.
基金Supported by the National Natural Science Foundation of China (Grant No. 10673005)Foundation of the Chinese Academy of Sciences (Grant No. KJCX2-YW-T13)
文摘Revised Hipparcos data were released by van Leeuwen in 2007.In this article revised Hipparcos trigo-nometrical parallaxes are used to derive a period-luminosity zero-point in the optical V band.Adopting a fixed slope of -2.81 from the LMC,a zero-point value of ρ= -1.37±0.07 is derived based on the method by Feast and Catchpole(1997).This value yields an LMC distance modulus of 18.64 mag,which makes a minor change in H0 expected from Feast and Catchpole's result in 1997.
