Multi dust species inner rim in magnetized protoplanetary disks

Abstract

The inner regions of protoplanetary disks, within ten astronomical units, are where terrestrial planets are born. By developing a new class of multi-dust radiative magnetized inner rim models, we can gain valuable insights into the conditions during planet formation. Our goal is twofold: to study the influence of highly refractory dust species on the inner rim shape and to determine how the magnetic field affects the inner disk structure. The resulting temperature and density structures are analyzed and compared to observations. The comparison focuses on a median SED of Herbig stars and interferometric constraints from the H, K, and N-band of three Herbig-type star-disk systems: HD 100546, HD 163296, and HD 169142. We investigate 1) the influence of a large-scale magnetic field on the inner disk structure and 2) the effect of having the four most important dust species (corundum, iron, forsterite, and enstatite) shaping the rim. We use frequency-dependent irradiation and the effect of accretion heating. With the Optool package, we obtain frequency-dependent opacities for each dust grain family and calculate the corresponding temperature-dependent Planck and Rosseland opacities. Our models with multiple dust species show a smoother and radially more extended inner rim. Strongly magnetized disks show a substantial increase in the emission flux between the L and N-bands. Weakly magnetized disk models with large-scale vertical magnetic fields < 0.3 Gauss at 1 au best fit with NIR interferometric observations. Our model comparison supports the existence of moderate magnetic fields ($\beta$ > $10^4$), which could still drive a magnetic wind in the inner disk. Our results show that multi-dust models, including magnetic fields, still lack NIR emission, especially in the H-band. One potential solution might be a heated gas disk or evaporating objects like planetesimals close to the star.