The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars
Using nearly 230,000 red clump stars selected from LAMOST and Gaia, we conduct a comprehensive analysis of the stellar age–velocity dispersion relations (AVRs) for various disk populations, within 5.0 ≤ R ≤ 15.0 kpc and ∣ Z ∣ ≤ 3.0 kpc. The AVRs of the whole red clump sample stars are accurately des...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ad9d41 |
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| author | Weixiang Sun Han Shen Biwei Jiang Xiaowei Liu |
| author_facet | Weixiang Sun Han Shen Biwei Jiang Xiaowei Liu |
| author_sort | Weixiang Sun |
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| description | Using nearly 230,000 red clump stars selected from LAMOST and Gaia, we conduct a comprehensive analysis of the stellar age–velocity dispersion relations (AVRs) for various disk populations, within 5.0 ≤ R ≤ 15.0 kpc and ∣ Z ∣ ≤ 3.0 kpc. The AVRs of the whole red clump sample stars are accurately described as σ _v = σ _v _,0 ( τ + 0.1) ${}^{{\beta }_{v}}$ , with β _R , β _ϕ , and β _Z displaying a global exponential decreasing trend with R , which may point to the difference in spatial distributions of various disk heating mechanisms. The measurements of β – R for various disks suggest that the thin disk exhibits a radial dependence, with a global exponential decreasing trend in β _R – R and β _Z – R , while β _ϕ remains a nearly constant value (around 0.20 ∼ 0.25) within 8.5 ≤ R ≤ 11.5 kpc. The thick disk displays a global increasing trend in β _R – R , β _ϕ – R , and β _Z – R . These results indicate that the thin disk stars are likely heated by long-term heating from giant molecular clouds and spiral arms, while thick disk stars are likely heated by some violent heating process from merger and accretion, and/or formed by the inside-out and upside-down star formation scenarios, and/or born in the chaotic mergers of gas-rich systems and/or turbulent interstellar medium. Our results also suggest that the disk perturbation by a recent minor merger from Sagittarius may have occurred within 3.0 Gyr. |
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| institution | Kabale University |
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| publishDate | 2025-01-01 |
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| spelling | doaj-art-694308b6c10f4d8783b34efd3923c8e42025-01-21T07:00:38ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01979210310.3847/1538-4357/ad9d41The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump StarsWeixiang Sun0https://orcid.org/0009-0005-9277-6758Han Shen1https://orcid.org/0000-0001-8962-4132Biwei Jiang2https://orcid.org/0000-0003-3168-2617Xiaowei Liu3https://orcid.org/0000-0003-1295-2909School of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of China ; sunweixiang@bnu.edu.cn, bjiang@bnu.edu.cnSchool of Physics, University of New South Wales , Kensington 2032, Australia; ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), AustraliaSchool of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of China ; sunweixiang@bnu.edu.cn, bjiang@bnu.edu.cnSouth-Western Institute for Astronomy Research, Yunnan University , Kunming 650500, People’s Republic of China ; x.liu@ynu.edu.cnUsing nearly 230,000 red clump stars selected from LAMOST and Gaia, we conduct a comprehensive analysis of the stellar age–velocity dispersion relations (AVRs) for various disk populations, within 5.0 ≤ R ≤ 15.0 kpc and ∣ Z ∣ ≤ 3.0 kpc. The AVRs of the whole red clump sample stars are accurately described as σ _v = σ _v _,0 ( τ + 0.1) ${}^{{\beta }_{v}}$ , with β _R , β _ϕ , and β _Z displaying a global exponential decreasing trend with R , which may point to the difference in spatial distributions of various disk heating mechanisms. The measurements of β – R for various disks suggest that the thin disk exhibits a radial dependence, with a global exponential decreasing trend in β _R – R and β _Z – R , while β _ϕ remains a nearly constant value (around 0.20 ∼ 0.25) within 8.5 ≤ R ≤ 11.5 kpc. The thick disk displays a global increasing trend in β _R – R , β _ϕ – R , and β _Z – R . These results indicate that the thin disk stars are likely heated by long-term heating from giant molecular clouds and spiral arms, while thick disk stars are likely heated by some violent heating process from merger and accretion, and/or formed by the inside-out and upside-down star formation scenarios, and/or born in the chaotic mergers of gas-rich systems and/or turbulent interstellar medium. Our results also suggest that the disk perturbation by a recent minor merger from Sagittarius may have occurred within 3.0 Gyr.https://doi.org/10.3847/1538-4357/ad9d41Stellar abundancesStellar kinematicsGalaxy kinematicsGalaxy structureMilky Way diskMilky Way dynamics |
| spellingShingle | Weixiang Sun Han Shen Biwei Jiang Xiaowei Liu The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars The Astrophysical Journal Stellar abundances Stellar kinematics Galaxy kinematics Galaxy structure Milky Way disk Milky Way dynamics |
| title | The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars |
| title_full | The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars |
| title_fullStr | The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars |
| title_full_unstemmed | The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars |
| title_short | The Age–Velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars |
| title_sort | age velocity dispersion relations of the galactic disk as revealed by the lamost gaia red clump stars |
| topic | Stellar abundances Stellar kinematics Galaxy kinematics Galaxy structure Milky Way disk Milky Way dynamics |
| url | https://doi.org/10.3847/1538-4357/ad9d41 |
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