| Popis: |
Context: Episodic accretion plays an important role during the early phases of star-formation. The main processes responsible for the episodic accretion events remain, however, unclear. Aims: Our main objective is to investigate the properties of FUors and EXors by analysing observational data, along with numerical hydrodynamics simulations of protostellar disks, stellar evolution models of outbursting stars and thermo-chemical models of star-disk systems in the outburst state. Our goal is to get a better understanding of the outburst processes and their respective origin. Methods: We used the radiation thermo-chemical code ProDiMo (PROtoplanetary DIsk MOdel) to match the dust emission and gas emission lines originating from the environment surrounding the FUor star Re 50 N IRS 1. Our model focusses on the observational data obtained by Herschel and Spitzer while we use archival photometry to complete the spectral energy distribution. Results: The modelling shows that the object is composed of a complex combination of several heating sources with different spatial distribution. Our model uses a massive envelope with an mass infall rate of 1.35 $\times 10^{-5}$ M$_{sun}$ yr$^{-1}$ to explain the continuum emission in the (sub-)mm regime. At the same time we fit the CO and $^{13}$CO ladders from 60 \textmu m to 650 \textmu m along with the two [\ion{O}{i}] lines centered at 63.18 and 145.53 \textmu m. To explain the strong CO emission at shorter wavelengths and the oxygen lines, we require a very warm disk due to a high disk accretion rate reaching 6 $\times 10^{-4}$ M$_{sun}$ yr$^{-1}$ and an additional UV field of 3\% of the overall emission to heat the disk. |
