The influence of dust composition on accretion outbursts

Episodic accretion outbursts have been shown to occur in protoplanetary discs, where they are caused by thermal instability at the inner edge of the dead zone. These outbursts periodically heat up the dead zone, which significantly alters the composition, chemistry and accretion onto the star. We investigate how these accretion outbursts affect the inner disc composition and how different dust compositions and properties affect the outburst dynamics. We ran vertically integrated axis-symmetric dust and gas evolution models using the TriPoD method, including dust opacity-dependent heating and cooling, a dead-zone model, and compositional tracking of dust, including the evaporation and condensation of volatiles. When dust is considered to consist of a condensation sequence of silicates and volatiles, the outburst evaporates most of the dust within 0.5 au. The fast re-condensation and subsequent viscous evolution reset the disc between bursts. Additionally, we found that the burst cycle period and maximum accretion rate directly correlate with the dust sublimation temperature.