3D physico-chemical model of a pre-stellar core

Pre-stellar cores represent the earliest stage of star- and planet-formation process. By characterizing physical chemical structure these we can establish initial conditions for star planet formation determine to what degree composition pre-stellar is inherited later stages. A 3D MHD model a core embedded in dynamic star-forming cloud post-processed using sequentially continuum radiative transfer, gas-grain model, line-radiative transfer model. Results are analyzed compared observations CH$_3$OH $c$-C$_3$H$_2$ L1544. Nine different models which compatible with observed segregation prototypical The able reproduce several aspects differentiation Extended methanol emission shifted towards colder more shielded regions envelope while overlaps dust continuum, consistent structure. Increasing strength interstellar radiation field or cosmic-ray ionization rate respect typical values assumed nearby leads synthetic maps that inconsistent Our shows dichotomy L1544 arise as result uneven illumination due asymmetrical environment within has formed. This highlights importance at core-cloud transition on chemistry cores.