2018/09/06 by Tamara Molyarova, Vitaly Akimkin, D. Semenov +10 · 55 citations
Chemistry · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Chemical evolution #Galaxy #Gas phase #Luminosity #Magnitude (astronomy) #Molecular Spectroscopy and Structure #Physics #Stars #Stellar, planetary, and galactic studies #Sublimation (psychology) #astro-ph.EP #astro-ph.GA #astro-ph.SR #msc:85-02
paper · pdf · doi:10.3847/1538-4357/aadfd9
published in The Astrophysical Journal 866(1), 46 (IOP Publishing) · accepted for publication in ApJ
arxiv created 2018/09/06 · openalex publication_date 2018/10/10 · arxiv updated 2018/10/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract The FU Ori–type young stellar objects are characterized by a sudden increase in luminosity by 1–2 orders of magnitude followed by a slow return to the pre-outburst state on timescales of ∼10–100 yr. The outburst strongly affects the entire disk, changing its thermal structure and radiation field. In this paper, using a detailed physical-chemical model, we study the impact of the FU Ori outburst on the disk chemical inventory. Our main goal is to identify gas-phase molecular tracers of the outburst activity that could be observed after the outburst with modern telescopes such as ALMA and NOEMA. We find that the majority of molecules experience a considerable increase in total disk gas-phase abundances due to the outburst, mainly due to the sublimation of their ices. Their return to the pre-outburst chemical state takes different amounts of time, from nearly instantaneous to very long. Among the former, we identify CO, NH 3 , C 2 H 6 , C 3 H 4 , etc. Their abundance evolution tightly follows the luminosity curve. For CO, the abundance increase does not exceed an order of magnitude, while for other tracers, the abundances increase by 2–5 orders of magnitude. Other molecules, like H 2 CO and NH 2 OH, have longer retention timescales, remaining in the gas phase for ∼10–10 3 yr after the end of the outburst. Thus, H 2 CO could be used as an indicator of the previous outbursts in the post-outburst FU Ori systems. We investigate the corresponding time-dependent chemistry in detail and present the most favorable transitions and ALMA configurations for future observations.