Atomic line radiative transfer with MCFOST

Aims. We present MCFOST-art, a new non-local thermodynamic equilibrium radiative transfer solver for multilevel atomic systems. The code is embedded in the 3D MCFOST and compatible with most of modules. versatile designed to model close environment stars 3D. Methods. solves statistical equations using Multilevel Accelerated Lambda Iteration (MALI) method. tested MCFOST-art on spherically symmetric models stellar photospheres as well standard solar atmosphere. computed level populations outgoing fluxes compared these values results TURBOspectrum RH codes. Calculations including expansion rotation atmosphere were also performed. both pure local out-of-equilibrium problems. Results. In all cases, from codes agree within few percent at wavelengths reach sub-percent between MCFOST-art. still note marginal discrepancies result different treatments background opacities some critical wavelength ranges.