천문우주과학과

일시 : 2024년 4월 24일 수요일 오후 4시 자4321호 강의실

연사 : 장석준 박사님 (Max Planck Institute for Astrophysics)

제목 : First detection and modeling spatially extended Lyα in T-Tauri star TW Hya 

초록 : UV radiation plays a crucial role in investigating the chemical composition of the protoplanetary disk. Hydrogen Lyman-α (Lyα) is one of the prominent UV emission lines in T-Tauri stars, with its resonance nature imprinting the physical properties of atomic hydrogen on Lyα observables. However, uncertainties arise due to the presence of dusty protoplanetary disks and optically thick accretion flows, questioning whether Lyα radiation from the central star reaches the disk & wind and influences their chemical composition. In this talk, I present spatially resolved Lyα emission across a protoplanetary disk in face-on T-Tauri star TW Hya, observed with HST-STIS. The observation reveals spatial extension over ~50 AU, with an asymmetric Lyα spectrum. To comprehensively interpret this spatially extended Lyα, we use a 3D Lyα radiative transfer simulation. Modeling Lyα through this code allows constraints on the physical properties of the neutral hydrogen in the wind and disk. Additionally, our simulation explores the Lyα radiative transfer effect in T-Tauri stars by computing the internal radiation field within the wind and disk. Understanding the role of Lyα emission in T-Tauri stars is pivotal for decoding the complex interactions between the winds, protoplanetary disks, and surrounding environments. Our observation and modeling of Lyα in TW Hya show the necessity of spatially resolved Lyα observation of a broad range of targets.