2.5-MHD models of circumstellar discs around FS CMa post-mergers: I. Non-stationary accretion stage

ABSTRACT We investigate the dynamic evolution of gaseous regions around FS CMa post-mergers. Owing to slow rotation central B-type star, dynamics is driven mainly by magnetic field star. Recent observations have allowed us set realistic initial conditions, such as value ($B_\star \approx 6\times 10^{3}\, \mathrm{G}$), mass star ($M_\star =6\, \mathrm{M}_\odot$), and disc density $\rho _{d0}\in [10^{-13}\, \mathrm{g\, cm^{-3}},10^{-11}\, \mathrm{g \, cm^{-3}}]$. use pluto code perform 2.5D magnetohydrodynamic simulations thin thick models. Especially relevant for interpretation observed properties post-mergers are results low-density discs, in which we find a jet emerging from inner edge disc, well formation so-called ‘hot plasmoid’ coronal region. Jets probably detected discrete absorption components resonance lines stars. Moreover, configuration plasma region favours appearance magnetocentrifugal winds disc. The currents towards created may explain accidentally material infall. structure significantly changed owing presence field. also responsible hot corona, several stars through Raman lines. Our valid all surrounded plasma, that is, some showing B[e] phenomenon.