The Effects of Accretion Feedback on Stellar Evolution in AGN Disks

Abstract

Stars embedded in the accretion disks of active galactic nuclei (AGN) can accrete rapidly from their surroundings, dramatically altering their structure and evolution. However, feedback from the release of gravitational potential energy and radiative enthalpy by accreting gas can limit accretion rates, as recently demonstrated in radiation hydrodynamics simulations. To determine the importance of these effects neglected in earlier stellar evolution calculations, we incorporate these feedback processes into a semianalytical model of stellar structure and evolution and conduct a suite of calculations spanning a broad parameter space of AGN disk conditions drawn from α -disk models with central black hole masses M • / M ⊙ ∈ [10 ⁶ , 10 ⁹ ]. We find that accretion feedback limits stellar accretion rates below ∼10 ⁻¹ M ⊙ yr ⁻¹ , reducing the sensitivity of stellar evolution to disk conditions. This suppression eliminates runaway accretion in models where it would otherwise occur, broadening the parameter space over which stars can reach long-lived “immortal” equilibria between accretion and mass loss. When gap opening is also accounted for, accretion feedback significantly alters stellar properties: it can reduce accretion and mass-loss rates by over an order of magnitude, reducing the strength of accretion shocks and thereby increasing equilibrium stellar masses and radii. These higher masses correspond to higher intrinsic luminosities, suggesting that neglecting accretion feedback may lead to an underestimate of disk chemical enrichment rates. Additionally, accretion feedback is important for predicting the properties of stellar populations within AGN disks, and associated transient phenomena.

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Cite

BibTeX RIS

BibTeX

@article{dittmann2026effects,
  title = {{The Effects of Accretion Feedback on Stellar Evolution in AGN Disks}},
  author = {Alexander J. Dittmann and Matteo Cantiello},
  journal = {The Astrophysical Journal},
  year = {2026},
  month = oct,
  doi = {10.3847/1538-4357/ae9c35},
  url = {https://iopscience.iop.org/article/10.3847/1538-4357/ae9c35},
  note = {CC BY 4.0},
}

RIS

TY  - JOUR
TI  - The Effects of Accretion Feedback on Stellar Evolution in AGN Disks
AU  - Alexander J. Dittmann
AU  - Matteo Cantiello
PY  - 2026
DA  - 2026/10/12
JO  - The Astrophysical Journal
DO  - 10.3847/1538-4357/ae9c35
UR  - https://iopscience.iop.org/article/10.3847/1538-4357/ae9c35
AB  - Stars embedded in the accretion disks of active galactic nuclei (AGN) can accrete rapidly from their surroundings, dramatically altering their structure and evolution. However, feedback from the release of gravitational potential energy and radiative enthalpy by accreting gas can limit accretion rates, as recently demonstrated in radiation hydrodynamics simulations. To determine the importance of these effects neglected in earlier stellar evolution calculations, we incorporate these feedback processes into a semianalytical model of stellar structure and evolution and conduct a suite of calculations spanning a broad parameter space of AGN disk conditions drawn from α -disk models with central black hole masses M • / M ⊙ ∈ [10 ⁶ , 10 ⁹ ]. We find that accretion feedback limits stellar accretion rates below ∼10 ⁻¹ M ⊙ yr ⁻¹ , reducing the sensitivity of stellar evolution to disk conditions. This suppression eliminates runaway accretion in models where it would otherwise occur, broadening the parameter space over which stars can reach long-lived “immortal” equilibria between accretion and mass loss. When gap opening is also accounted for, accretion feedback significantly alters stellar properties: it can reduce accretion and mass-loss rates by over an order of magnitude, reducing the strength of accretion shocks and thereby increasing equilibrium stellar masses and radii. These higher masses correspond to higher intrinsic luminosities, suggesting that neglecting accretion feedback may lead to an underestimate of disk chemical enrichment rates. Additionally, accretion feedback is important for predicting the properties of stellar populations within AGN disks, and associated transient phenomena.
SN  - 0004-637X
SN  - 1538-4357
ER  -

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