恒星内部的超声速对流区

依传统的局部混合长理论进行了对流包层模型计算,在黄红巨星和超巨星对流区的顶部出现超声速对流的情况,这与局部对流理论本身是不自恰的．文章详细分析了恒星大气超声速对流的成因,并按照星族Ⅰ恒星的演化轨迹,在赫罗图上给出了出现超声速对流的区域．其结果是。在演化过程中, (1)低质量星基本不出现超声速对流; (2)中等质量星的超声速对流主要出现在3．6<lgTe<4的区域,且从左下往右上倾斜,超声速对流出现在氢的电离区．对质量稍大的星,超声速对流区域延伸到红巨星部分; (3)大质量星在脱离主序后不久便进入超声速对流区,越大质量的星发生超声速对流的年龄越早．对蓝超巨星,超声速对流出现在lgT-5．3(铁的吸收峰)和氮的二次电离区,而红、黄巨星和超巨星,超声速对流出现在氢的电离区．

A proposed direct measurement of cross section at Gamow window for key reaction 19F(p,α) 16O in Asymptotic Giant Branch stars with a planned accelerator in CJPL

In 2014, the National Natural Science Foundation of China （NSFC） approved the Jinping Underground Nuclear Astrophysics laboratory （JUNA） project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch （AGB） stars, measuring the key 19F（p,a）16O reaction at effective burning energies （i.e., at Gamow window） is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.