Accretion of Active Galactic Nucleus Stars Under the Influence of Disk Geometry
Massive stars can form within or be captured by active galactic nucleus disks, influencing both the thermal structure and metallicity of the disk environment. In a previous work, we investigated isotropic accretion onto massive stars from a gas-rich, high-entropy background. Here, we consider a more...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/addd0a |
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| author | Yi-Xian Chen Yan-Fei Jiang Jeremy Goodman |
| author_facet | Yi-Xian Chen Yan-Fei Jiang Jeremy Goodman |
| author_sort | Yi-Xian Chen |
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| description | Massive stars can form within or be captured by active galactic nucleus disks, influencing both the thermal structure and metallicity of the disk environment. In a previous work, we investigated isotropic accretion onto massive stars from a gas-rich, high-entropy background. Here, we consider a more realistic scenario, by incorporating the stratified geometry of the background disk in our 3D radiation hydrodynamic simulations. We find that the accretion remains relatively isotropic when the disk is hot enough and the scale height is thicker than the accretion flow’s nominal supersonic critical radius R _crit (subthermal). However, when the disk becomes cold, the accretion flow becomes significantly anisotropic (superthermal). Escaping stellar and accretion luminosity can drive super-Eddington outflows in the polar region, while rapid accretion is sustained along the midplane. Eventually, the effective cross section is constrained by the Hill radius and the disk scale height rather than the critical radius when the disk is cold enough. For our setup (stellar mass ∼50 M _⊙ and background density ρ ∼ 10 ^−10 g cm ^−3 ), the accretion rate is capped below ∼0.02 M _⊙ yr ^−1 and the effective accretion parameter α ∼ 10 ^−1 over the disk temperature range 3–7 × 10 ^4 K. Spiral arms facilitate inward mass flux by driving outward angular momentum transport. Gap-opening effects may further reduce the long-term accretion rate, although to confirm this would require global simulations evolved over much longer viscous timescales. |
| format | Article |
| id | doaj-art-5c6bc21b82574e53bd393d605178bcdb |
| institution | DOAJ |
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| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-5c6bc21b82574e53bd393d605178bcdb2025-08-20T02:41:33ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01987218810.3847/1538-4357/addd0aAccretion of Active Galactic Nucleus Stars Under the Influence of Disk GeometryYi-Xian Chen0https://orcid.org/0000-0003-3792-2888Yan-Fei Jiang1https://orcid.org/0000-0002-2624-3399Jeremy Goodman2https://orcid.org/0000-0002-6710-7748Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USACenter for Computational Astrophysics, Flatiron Institute , New York, NY 10010, USADepartment of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USAMassive stars can form within or be captured by active galactic nucleus disks, influencing both the thermal structure and metallicity of the disk environment. In a previous work, we investigated isotropic accretion onto massive stars from a gas-rich, high-entropy background. Here, we consider a more realistic scenario, by incorporating the stratified geometry of the background disk in our 3D radiation hydrodynamic simulations. We find that the accretion remains relatively isotropic when the disk is hot enough and the scale height is thicker than the accretion flow’s nominal supersonic critical radius R _crit (subthermal). However, when the disk becomes cold, the accretion flow becomes significantly anisotropic (superthermal). Escaping stellar and accretion luminosity can drive super-Eddington outflows in the polar region, while rapid accretion is sustained along the midplane. Eventually, the effective cross section is constrained by the Hill radius and the disk scale height rather than the critical radius when the disk is cold enough. For our setup (stellar mass ∼50 M _⊙ and background density ρ ∼ 10 ^−10 g cm ^−3 ), the accretion rate is capped below ∼0.02 M _⊙ yr ^−1 and the effective accretion parameter α ∼ 10 ^−1 over the disk temperature range 3–7 × 10 ^4 K. Spiral arms facilitate inward mass flux by driving outward angular momentum transport. Gap-opening effects may further reduce the long-term accretion rate, although to confirm this would require global simulations evolved over much longer viscous timescales.https://doi.org/10.3847/1538-4357/addd0aMassive starsActive galactic nucleiAccretionRadiative transfer simulations |
| spellingShingle | Yi-Xian Chen Yan-Fei Jiang Jeremy Goodman Accretion of Active Galactic Nucleus Stars Under the Influence of Disk Geometry The Astrophysical Journal Massive stars Active galactic nuclei Accretion Radiative transfer simulations |
| title | Accretion of Active Galactic Nucleus Stars Under the Influence of Disk Geometry |
| title_full | Accretion of Active Galactic Nucleus Stars Under the Influence of Disk Geometry |
| title_fullStr | Accretion of Active Galactic Nucleus Stars Under the Influence of Disk Geometry |
| title_full_unstemmed | Accretion of Active Galactic Nucleus Stars Under the Influence of Disk Geometry |
| title_short | Accretion of Active Galactic Nucleus Stars Under the Influence of Disk Geometry |
| title_sort | accretion of active galactic nucleus stars under the influence of disk geometry |
| topic | Massive stars Active galactic nuclei Accretion Radiative transfer simulations |
| url | https://doi.org/10.3847/1538-4357/addd0a |
| work_keys_str_mv | AT yixianchen accretionofactivegalacticnucleusstarsundertheinfluenceofdiskgeometry AT yanfeijiang accretionofactivegalacticnucleusstarsundertheinfluenceofdiskgeometry AT jeremygoodman accretionofactivegalacticnucleusstarsundertheinfluenceofdiskgeometry |