Please use this identifier to cite or link to this item:
|Title:||Accretion Bursts in Low-metallicity Protostellar Disks|
|Authors:||Vorobyov, E. I.|
Elbakyan, V. G.
|Citation:||Accretion Bursts in Low-metallicity Protostellar Disks / E. I. Vorobyov, V. G. Elbakyan, K. Omukai et al. — DOI 10.1134/S0081543820020078 // Astronomy and Astrophysics. — 2020. — Vol. 641. — A72.|
|Abstract:||Aims. The early evolution of protostellar disks with metallicities in the Zâ =â 1.0â-â 0.01â ZâŠ range was studied with a particular emphasis on the strength of gravitational instability and the nature of protostellar accretion in low-metallicity systems. Methods. Numerical hydrodynamics simulations in the thin-disk limit were employed that feature separate gas and dust temperatures, and disk mass-loading from the infalling parent cloud cores. Models with cloud cores of similar initial mass and rotation pattern but distinct metallicity were considered to distinguish the effect of metallicity from that of the initial conditions. Results. The early stages of disk evolution in low-metallicity models are characterized by vigorous gravitational instability and fragmentation. Disk instability is sustained by continual mass-loading from the collapsing core. The time period that is covered by this unstable stage is much shorter in the Zâ =â 0.01â ZâŠ models than in their higher metallicity counterparts thanks to the higher rates of mass infall caused by higher gas temperatures (which decouple from lower dust temperatures) in the inner parts of collapsing cores. Protostellar accretion rates are highly variable in the low-metallicity models reflecting the highly dynamic nature of the corresponding protostellar disks. The low-metallicity systems feature short but energetic episodes of mass accretion caused by infall of inward-migrating gaseous clumps that form via gravitational fragmentation of protostellar disks. These bursts seem to be more numerous and last longer in the Zâ =â 0.1â ZâŠ models than in the Zâ =â 0.01â ZâŠ case. Conclusions. Variable protostellar accretion with episodic bursts is not a particular feature of solar metallicity disks. It is also inherent to gravitationally unstable disks with metallicities up to 100 times lower than solar. © ESO 2020.|
HIGHER GAS TEMPERATURE
|metadata.dc.description.sponsorship:||Acknowledgements. We are thankful to the anonymous referee for useful comments that helped to improve the manuscript. E. I. V. and M. G. acknowledge support from the Austrian Science Fund (FWF) under research grant P31635-N27. V. G. E. acknowledges the Swedish Institute for a visitor Grant allowing to conduct research at Lund University. The simulations were performed on the Vienna Scientific Cluster.|
|Appears in Collections:||Научные публикации, проиндексированные в SCOPUS и WoS CC|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.