Investigation Of Astrophysical Origin Of The Elements In The Globular Cluster M2

As is known to all,our universe is originated from a big bang in 140 Gyr ago.The globular cluster is an ancient,long-lived member of the Galaxy,and is known as the active fossil of galaxy evolution.The observation shows that different elements such as the ?-elements,the iron group elements and the neutron-capture elements reveal different abundance trends with the chang of [Fe/H] in the globular cluster M2.The research of the elemental abundances in the sample stars can help us better understand the history and evolution of the globular cluster M2.There are two parts included in the paper:The first part presents the five components elemental abundance model that independent of galaxy chemical evolution,and its calculation method.And then,we fit the observations abundance of elements of the14 sample stars(6 r-only stars,4 s stars,4 metal rich stars)belonging to the globular cluster M2,and show the best fitting result subsequently.Through the analysis of the overall distribution to the coefficients of the results,we can draw a conclusion that the contribution of the r-process components to the elemental abundance is always in a dominant position,within the range of [Fe/H] observed by the sample star.The contribution to the elemental abundance forms the weak s-process component and the SNe Ia component rises slowly as the [Fe/H] increases,although the two conponents' contribution is relatively small.The four s stars have a typical s-process feature,whose s-process contribution is over abundance.In addition,it is valid for us to use the five components elemental abundance model in our work by the overall fitting effect diagram given in this paper.In the part two,we discuss the astrophysical origin of the ?-elements,the iron group elements and the neutron-capture elements,and come to the conclusion of this paper.The contribution of the primary process components of the mass star to the abundance of the ?-elements and the iron group elements has played a dominant role within the [Fe/H] range,and appears a varying degrees of decline along with the [Fe/H] increase,in the narrow range of the observed metal abundance(-1.8<[Fe/H]<-0.9).However,the difference is that with the increase of [Fe/H],the contribution of the secondary process components to large mass stars to the abundance of the iron group elements is increasing.The lighter neutron capture elements such as Y and Zr,whose abundance mainly come from the main s-process component and the weak r-process component.And those two compents contribution to elemental abundances varies slowly with increasing of [Fe/H].While the astrophysical origin of the heavier neutron capture element is the main r-process and the main s-process.For those elements that are heavier than Eu,the contribution of the main r-process component is always dominant.The four s stars are special among the entire sample stars,whose elemental abundance of the main s-process components contributes over abundance.In view of this situation,we infer that it is likely to be polluted by the low mass AGB stars.