Extinction correction is crucial for understanding the intrinsic properties of celestial objects within and beyond the Milky Way, especially with Gaia’s photometric precision reaching millimagnitude levels. Leveraging millions of high-quality spectra and precise atmospheric parameters from LAMOST, we have achieved unprecedented accuracy in extinction measurements. Using the “star-pair” technique, we derived high-precision multi-band reddening data and extinction curves for millions of stars, leading to notable improvements in the accuracy of reddening correction for the Milky Way dust. We quantified the “bandwidth effects” of extinction and established an empirical relationship between reddening coefficients, temperature, and extinction, resolving previous inconsistencies. We also mapped the 2D distribution of the dust property parameter Rv across the Milky Way, revealing that Rv values in molecular clouds are lower than in surrounding regions, possibly due to the protection of small dust grains. Recently, combining Gaia XP spectra, we directly measured the mean extinction curve of the Milky Way using ~370,000 high-quality spectra. This effort confirmed known intermediate-scale structures and discovered a new one. These structures show correlations with extinction magnitude, Rv, and diffuse interstellar bands (DIBs).
BIO
Ruoyi Zhang is a Ph.D student in the School of Physics and Astronomy at Beijing Normal University. He received his bachelor’s degree from Beijing Normal University in 2019 and completed a one-year visit at the Max Planck Institute in 2024. His research interests include dust, diffuse interstellar bands (DIBs), and other interstellar medium topics. He is currently focusing on the spatial distribution/variation of dust, dust properties, and extinction curves within the Milky Way.
Host: Shuo Zhang
