New insights into the limit of the magnetic monopole flux and the heating source in white dwarfs

Based on the magnetic monopole (MM) catalytic nuclear decay (Rubakov-Callan (RC) effect), we propose five new models to discuss the limit of the MM flux and the heating energy resources of white dwarfs (WDs) based on observations of 13 red giant branch (RGB) stars. We find that the number of MMs captured can reach a maximum value of 9.1223x10(24) when m =10(17) Gev, n(B) =5.99 x 10(31) cm(-3), phi =7.59 x 10(-26)cm(-2)s(-1)sr(-1). The good agreement of our calculated luminosities for WDs with observation provides support for our model based on the RC effect by MMs. We obtain a new limit of the MM flux of xi =phi <sigma(m)v(T)> -28 <= 9.0935 x 10(-13)cm(-2)s(-1)sr(-1), and xi <= 4.9950 x 10(-13)cm(-2)s(-1)sr(-1) at n(B) =5.99 x 10(31)cm(-3) when = 10(15)GeV, beta=9.4868 x 10(-3), and m = 10(17)GeV, beta =10(-3), respectively. Our results show that the RC effect could cause heating that prevents white dwarfs from cooling down into a stellar graveyard. Our results will also provide a new idea for further research on the upper limit of MM flow (note: n(B),sigma(m),m,phi,xi are the baryon number density, reaction cross section, mass, MM flux, and the new limit of the MM flux, respectively, and beta = v(T)/c is the ratio of the speed of MMs to that of light).