A Tale of Two Dust Disks in Our Milky Way

Fuente: arXiv
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Autori principali: Zhang, Ruoyi, Yuan, Haibo, Chen, Bingqiu, Xiang, Maosheng, Huang, Yang, Liu, Xiaowei, Liu, Jifeng
Natura: Preprint
Pubblicazione: 2026
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author Zhang, Ruoyi
Yuan, Haibo
Chen, Bingqiu
Xiang, Maosheng
Huang, Yang
Liu, Xiaowei
Liu, Jifeng
author_facet Zhang, Ruoyi
Yuan, Haibo
Chen, Bingqiu
Xiang, Maosheng
Huang, Yang
Liu, Xiaowei
Liu, Jifeng
contents Cosmic dust plays a vital role in stellar and galactic formation and evolution, but its three-dimensional structure in the Milky Way has remained unclear due to insufficient precise reddening and distance measurements. Although early studies typically adopted a single-disk model, we detect two distinct components at Galactocentric distances of 5-14 kpc, enabled by photometric, spectroscopic, and astrometric measurements of over 5 million stars. The thin dust disk's scale height increases radially from 60 to 200 pc, while the thick disk grows from 300 to 800 pc. For the first time, we find the thin and thick dust disk correlates spatially with molecular and atomic hydrogen disk, respectively. The thin, thick, and combined disks have scale lengths of 9.6+1.2-1.1 kpc, 4.2+0.4-0.3 kpc, and 6.6+0.3-0.3 kpc, respectively. The gas-to-dust ratio shows an exponential radial gradient, increasing from around 60 at 5 kpc to around 470 at 14 kpc. These findings provide new insights into dust morphology in the Galaxy and raise fundamental questions that require further investigation.
format Preprint
id arxiv_https___arxiv_org_abs_2601_02724
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Tale of Two Dust Disks in Our Milky Way
Zhang, Ruoyi
Yuan, Haibo
Chen, Bingqiu
Xiang, Maosheng
Huang, Yang
Liu, Xiaowei
Liu, Jifeng
Astrophysics of Galaxies
Cosmic dust plays a vital role in stellar and galactic formation and evolution, but its three-dimensional structure in the Milky Way has remained unclear due to insufficient precise reddening and distance measurements. Although early studies typically adopted a single-disk model, we detect two distinct components at Galactocentric distances of 5-14 kpc, enabled by photometric, spectroscopic, and astrometric measurements of over 5 million stars. The thin dust disk's scale height increases radially from 60 to 200 pc, while the thick disk grows from 300 to 800 pc. For the first time, we find the thin and thick dust disk correlates spatially with molecular and atomic hydrogen disk, respectively. The thin, thick, and combined disks have scale lengths of 9.6+1.2-1.1 kpc, 4.2+0.4-0.3 kpc, and 6.6+0.3-0.3 kpc, respectively. The gas-to-dust ratio shows an exponential radial gradient, increasing from around 60 at 5 kpc to around 470 at 14 kpc. These findings provide new insights into dust morphology in the Galaxy and raise fundamental questions that require further investigation.
title A Tale of Two Dust Disks in Our Milky Way
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2601.02724