Colloquium on Mar. 27, 2025

Multi-band Studies of Dust Extinction Revealed by Gaia、JWST, and the Implied Dust Physics

Speaker: Shu Wang (NAOC)

Venue: SWIFAR Building 2111

Time: 16:00 PM, Thursday, Mar. 27, 2025

Abstract:

Cosmic dust is ubiquitous in various environments, from planets and stars to galaxies. It not only significantly affects the analysis of the physical properties of stars and galaxies but also plays a crucial role in their evolution. We come from dust and will eventually return to it. But what exactly is dust? This talk presents a systematic study of multi-band dust extinction laws and their implications for dust physics. For the first time, we have modeled the curvature structure of extinction curves, constructing high-precision Rv-dependent extinction laws for the Milky Way and the Magellanic Clouds, reducing the uncertainty from 20% to an impressive 3%. Additionally, we have developed new extinction tracers and analytical methods, establishing the first JWST-based near-infrared extinction law of the Milky Way, which resolves the long-standing debate on whether near-infrared extinction laws are universal and provides essential calibration tools for JWST observations. By combining extinction studies with dust physical modeling, we further reveal the physical characteristics of dust, such as size distribution and chemical composition. Finally, using brown dwarfs as an example, we explore dust properties in stars of different masses and evolutionary stages, and discuss the observational prospects and impact of dust studies in the JWST era.