Shadow-Based Framework for Estimating Transition Disk Geometries

TL;DR

This paper presents a new method to determine the three-dimensional geometry of misaligned transition disks using shadow analysis in scattered light images, applied to the HD 100453 system.

Contribution

It introduces a novel approach to infer 3D disk structures from shadow features, enhancing understanding of disk misalignments and vertical geometries.

Findings

Inner disk is misaligned by ~70 degrees.

Inner disk surface aspect ratio is 0.17.

Outer disk surface height distribution characterized.

Abstract

Some transition disks host misaligned inner disks with radii of several au. Understanding the geometric and physical properties of these misaligned disks is essential for advancing terrestrial planet formation models. This study introduces a novel method to infer the three-dimensional structures of both inner and outer disks by analyzing non-axisymmetric shadows and the horizon in optical and infrared scattered light images of the outer disk. This method was applied to the HD 100453 system, in which infrared scattered light images from the Very Large Telescope revealed disk shadows. These results indicate that the inner disk is misaligned by $\sim$70$^{\circ}$ relative to the outer disk, which is consistent with the results of previous studies. The aspect ratio of the inner disk surface was estimated to be 0.17, which may reflect the surface height of the optically thick dusty component due to vertical lofting by MHD winds or turbulence. In addition, the surface height distribution of the outer disk was characterized, providing novel insights into its vertical structure.