Anibal Sierra¹, Susana Lizano¹, Enrique Macías², Carlos Carrasco-González¹, Mayra Osorio³, and Mario Flock⁴
Astrophysical Journal 876, 7 Link to Article [DOI: 10.3847/1538-4357/ab1265 ]
¹Instituto de Radioastronomía y Astrofísica, UNAM, Apartado Postal 3-72, 58089 Morelia Michoacán, México
²Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA
³Instituto de Astrofísica de Andalucía (CSIC) Glorieta de la Astronomía s/n E-18008 Granada, Spain
⁴Max Planck Institute fűr Astronomy (MPIA), Kőnigsthul 17, D-69117 Heidelberg, Germany

We study dust concentration in axisymmetric gas rings in protoplanetary disks. Given the gas surface density, we derived an analytical total dust surface density by taking into account the differential concentration of all grain sizes. This model allows us to predict the local dust-to-gas mass ratio and the slope of the particle size distribution, as a function of radius. We test this analytical model by comparing it with a 3D magnetohydrodynamical simulation of dust evolution in an accretion disk. The model is also applied to the disk around HD 169142. By fitting the disk continuum observations simultaneously at λ = 0.87, 1.3, and 3.0 mm, we obtain a global dust-to-gas mass ratio and a viscosity coefficient α = 1.35 × 10⁻². This model can be easily implemented in numerical simulations of accretion disks.