Chemical Signatures of the FU Ori Outbursts

摘要: The FU Ori-type young stellar objects are characterized by a sudden increase in luminosity 1$-$2 orders of magnitude, followed slow return to the pre-outburst state on timescales $\sim$10$-$100 yr. outburst strongly affects entire disk, changing its thermal structure and radiation field. In this paper, using detailed physical-chemical model we study impact Ori disk chemical inventory. Our main goal is identify gas-phase molecular tracers activity that could be observed after with modern telescopes such as ALMA NOEMA. We find majority molecules experience considerable total abundances due outburst, mainly sublimation their ices. Their takes different amounts time, from nearly instantaneous very long. Among former ones CO, NH$_3$, C$_2$H$_6$, C$_3$H$_4$, etc. abundance evolution tightly follows curve. For CO does not exceed an order while for other 2$-$5 magnitude. Other like H$_2$CO NH$_2$OH have longer retention timescales, remaining gas phase $\sim10-10^3$ yr end outburst. Thus used indicator previous outbursts post-outburst systems. investigate corresponding time-dependent chemistry detail present most favorable transitions configurations future observations.