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The Temporal Requirements of Directly Observing Self-gravitating Spiral Waves in Protoplanetary Disks with ALMA

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journal contribution
posted on 18.06.2019, 09:11 by C Hall, R Dong, K Rice, TJ Harries, J Najita, R Alexander, S Brittain
We investigate how the detectability of signatures of self-gravity in a protoplanetary disk depends on its temporal evolution. We run a one-dimensional model for secular timescales to follow the disk mass as a function of time. We then combine this with three-dimensional global hydrodynamics simulations that employ a hybrid radiative transfer method to approximate realistic heating and cooling. We simulate ALMA continuum observations of these systems and find that structures induced by the gravitational instability (GI) are readily detectable when q = Mdisk/M*  0.25 and Router  100 au. The high accretion rate generated by gravito-turbulence in such a massive disk drains its mass to below the detection threshold in ∼104 years, or approximately 1% of the typical disk lifetime. Therefore, disks with spiral arms detected in ALMA dust observations, if generated by self-gravity, must either be still receiving infall to maintain a high q value, or have just emerged from their natal envelope. Detection of substructure in systems with lower q is possible, but would require a specialist integration with the most extended configuration over several days. This disfavors the possibility of GI-caused spiral structure in systems with q < 0.25 being detected in relatively short integration times, such as those found in the DSHARP ALMA survey. We find no temporal dependence of detectability on dynamical timescales.


C.H. is a Winton Fellow, and this research has been supported by Winton Philanthropies. This research used the ALICE2 High Performance Computing Facility at the University of Leicester. This research also used the DiRAC DIaL (Data Intensive at Leicester) facility. We would like to thank Daniel Price for his publicly available SPH plotting code SPLASH (Price 2007), which we have made use of in this paper. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 681601). T.J.H. acknowledges funding from Exeter's STFC Consolidated Grant (ST/M00127X/1).



Astrophysical Journal, 2019, 871 (2)

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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American Astronomical Society, IOP Publishing





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