The Ultraviolet to Mid-infrared Extinction Law of the Taurus Molecular Cloud Based on the Gaia DR3, GALEX, APASS, Pan-STARRS1, 2MASS, and WISE Surveys

Abstract

Interstellar-dust extinction law is essential for interpreting observations. In this work, we investigate the ultraviolet (UV)–mid-infrared (IR) extinction law of the Taurus molecular cloud and its possible variations. We select 504,988 dwarf stars (4200 K ≤ T eff ≤ 8000 K) and 4757 giant stars (4200 K ≤ T eff ≤ 5200 K) based on the stellar parameters of Gaia DR3 as tracers. We establish the T eff–intrinsic color relations and determine the intrinsic color indices and color excesses for different types of stars. In the determination of color excess ratios (CERs), we analyze and correct the curvature of CERs and derive the UV–mid-IR CERs of 16 bands. We consider different effective wavelengths for different types of stars when converting CERs to relative extinction and obtain the extinction law with a better wavelength resolution. In addition, we analyze the possible regional variation of extinction law and derive the average extinction law of R V = 3.13 ± 0.32 for the Taurus molecular cloud. Only 0.9% of subregions have deviations >3σ, indicating limited regional variation in the extinction law. We also discuss the effect of Gaia T eff overestimation on the determination of the Taurus extinction law and find that the effect is negligible.