Contribution of Proton Capture Reactions to the Ascertained Abundance of Fluorine in the Evolved Stars of Globular Cluster M4, M22, 47 Tuc and NGC 6397

Abstract

The origin of the abundance pattern and also the (anti)correlation present among the elements found in stars of globular clusters (GCs) remains unimproved until date. The proton-capture reactions are presently recognised in concert of the necessary candidates for that sort of observed behaviour in the second generation stars. We tend to propose a reaction network of a nuclear cycle namely carbon–nitrogen–oxygen–fluorine (CNOF) at evolved stellar condition since fluorine $$(^{19}\hbox {F})$$ is one such element which gets plagued by proton capture reactions. The stellar temperature thought about here ranges from $$2\times 10^{7}$$ to $$10\times 10^{7}$$ K and there has been an accretion occuring, with material density being $$10^{2}\hbox { g/cm}^{3}$$ and $$10^{3}\hbox { g/cm}^{3}$$ . Such kind of temperature density conditions are probably going to be prevailing within the H-burning shell of evolved stars. The estimated abundances of $$^{19}\hbox {F}$$ are then matched with the info that has been determined for a few some metal-poor giants of GC $$\hbox {M}4,\hbox { M}22,\, 47$$ Tuc as well as NGC 6397. As far as the comparison between the observed and calculated abundances is concerned, it is found that the abundance of $$^{19}\hbox {F}$$ have shown an excellent agreement with the observed abundances with a correlation coefficent above 0.9, supporting the incidence of that nuclear cycle at the adopted temperature density conditions.