It remains unclear what mechanism is driving the evolution of protoplanetary disks. Direct detection of the main candidates, either turbulence driven by magnetorotational instabilities or magnetohydrodynamical disk winds, has proven difficult, leaving the time evolution of the disk size as one of the most promising observables able to differentiate between these two mechanisms. But to do so successfully, we need to understand what the observed gas disk size actually traces. We studied the relation between R-CO,R-90%, the radius that encloses 90% of the (CO)-C-12 flux, and R-c, the radius that encodes the physical disk size, in order to provide simple prescriptions for conversions between these two sizes. For an extensive grid of thermochemical models, we calculate R-CO,R- 90% from synthetic observations and relate properties measured at this radius, such as the gas column density, to bulk disk properties, such as R-c and the disk mass M-disk. We found an empirical correlation between the gas column density at R-CO,R- 90% and disk mass: N-gas (R-CO,R- 90%) approximate to 3.73 x 10(21) M-disk/M-circle dot cm(-2). Using this correlation we derive an analytical prescription of R-CO,R- 90% that only depends on Rc and Mdisk. We derive R-c for disks in Lupus, Upper Sco, Taurus, and the DSHARP sample, finding that disks in the older Upper Sco region are significantly smaller (< R-c > = 4.8 au) than disks in the younger Lupus and Taurus regions (< R-c > = 19.8 and 20.9 au, respectively). This temporal decrease in R-c goes against predictions of both viscous and wind-driven evolution, but could be a sign of significant external photoevaporation truncating disks in Upper Sco.

How Large Is a Disk-What Do Protoplanetary Disk Gas Sizes Really Mean? / L. Trapman, G. Rosotti, K. Zhang, B. Tabone. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - 954:1(2023 Sep 01), pp. 41.1-41.19. [10.3847/1538-4357/ace7d1]

How Large Is a Disk-What Do Protoplanetary Disk Gas Sizes Really Mean?

G. Rosotti
Secondo
;
2023

Abstract

It remains unclear what mechanism is driving the evolution of protoplanetary disks. Direct detection of the main candidates, either turbulence driven by magnetorotational instabilities or magnetohydrodynamical disk winds, has proven difficult, leaving the time evolution of the disk size as one of the most promising observables able to differentiate between these two mechanisms. But to do so successfully, we need to understand what the observed gas disk size actually traces. We studied the relation between R-CO,R-90%, the radius that encloses 90% of the (CO)-C-12 flux, and R-c, the radius that encodes the physical disk size, in order to provide simple prescriptions for conversions between these two sizes. For an extensive grid of thermochemical models, we calculate R-CO,R- 90% from synthetic observations and relate properties measured at this radius, such as the gas column density, to bulk disk properties, such as R-c and the disk mass M-disk. We found an empirical correlation between the gas column density at R-CO,R- 90% and disk mass: N-gas (R-CO,R- 90%) approximate to 3.73 x 10(21) M-disk/M-circle dot cm(-2). Using this correlation we derive an analytical prescription of R-CO,R- 90% that only depends on Rc and Mdisk. We derive R-c for disks in Lupus, Upper Sco, Taurus, and the DSHARP sample, finding that disks in the older Upper Sco region are significantly smaller (< R-c > = 4.8 au) than disks in the younger Lupus and Taurus regions (< R-c > = 19.8 and 20.9 au, respectively). This temporal decrease in R-c goes against predictions of both viscous and wind-driven evolution, but could be a sign of significant external photoevaporation truncating disks in Upper Sco.
Settore FIS/05 - Astronomia e Astrofisica
   Rebuilding the foundations of planet formation: proto-planetary disc evolution (DiscEvol)
   DiscEvol
   EUROPEAN COMMISSION
   101039651
1-set-2023
22-ago-2023
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1001834
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