Star–Disk Collisions. II. Debris Stream Dynamics and Implications for Quasiperiodic Eruptions and Other Transients Near Supermassive Black Holes
4 affiliations
- 1Princeton University
- 2Flatiron Institute
- 3Columbia University
- 4New York University
Abstract
Quasiperiodic eruptions (QPEs) are repeating soft X-ray nuclear transients with recurrence times of hours–days and flare duty cycles of ∼10%–20%. QPEs can be modeled as a stellar-mass orbiter that intersects an accretion disk, producing a shocked debris cloud and a flare. We present 3D Athena++ hydrodynamic simulations of star–disk interactions around a 10 ⁶ M ⊙ supermassive black hole, including the black hole’s tidal potential, the disk’s Keplerian rotation, and orbital periods similar to those observed. After each disk encounter, freshly stripped stellar debris exits the Hill sphere to form an extended, asymmetric, roughly triaxial stream. Subsequent stream–disk collisions shock both stellar debris and disk gas to high specific energies and drive a wind-like outflow. At larger orbital periods the shocked stellar debris dominates the high specific energy debris, while at shorter periods the shocked disk energy can be similar. From the shocked stellar mass measured over time, we infer flare durations set by the stream–disk collision time, consistent with the observed constant duty cycle of ∼10%–20%, independent of orbital period. The total shocked debris energy is broadly consistent with QPE flare energetics at shorter orbital periods. Our results favor one observable flare per stellar orbit, except perhaps at the shortest periods where the shocked stellar and disk energetics can be similar. Variations in the stream’s center of mass relative to the star, its density, and other properties can produce diverse shifts in the flare’s peak relative to the star–disk collision. We discuss implications for QPE timing and other transients in galactic nuclei.
Related
- Secular Evolution of Quasiperiodic Eruptions: eRO-QPE2
- Quasiperiodic Eruptions from Recurrent Satellite Black Hole Transits through Magnetized Galactic Nucleus Accretion Disks
- A Unified Timescale Relation for Quasi-Periodic Eruptions and Repeated Nuclear Transients
- Unlocking the Quasiperiodic Eruption Mystery: Star–Disk Collisions in Realistic Active Galactic Nucleus Disks
- Stellar Collisions from Self-consistent Stellar Dynamics around Growing Supermassive Black Holes
BibTeX
@article{yao2026stardisk,
title = {{Star–Disk Collisions. II. Debris Stream Dynamics and Implications for Quasiperiodic Eruptions and Other Transients Near Supermassive Black Holes}},
author = {Philippe Z. Yao and Eliot Quataert and Yan-Fei 燕飞 Jiang 姜 and Itai Linial},
journal = {The Astrophysical Journal},
year = {2026},
month = nov,
doi = {10.3847/1538-4357/aeaa4d},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aeaa4d},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Star–Disk Collisions. II. Debris Stream Dynamics and Implications for Quasiperiodic Eruptions and Other Transients Near Supermassive Black Holes
AU - Philippe Z. Yao
AU - Eliot Quataert
AU - Yan-Fei 燕飞 Jiang 姜
AU - Itai Linial
PY - 2026
DA - 2026/11/03
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aeaa4d
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aeaa4d
AB - Quasiperiodic eruptions (QPEs) are repeating soft X-ray nuclear transients with recurrence times of hours–days and flare duty cycles of ∼10%–20%. QPEs can be modeled as a stellar-mass orbiter that intersects an accretion disk, producing a shocked debris cloud and a flare. We present 3D Athena++ hydrodynamic simulations of star–disk interactions around a 10 ⁶ M ⊙ supermassive black hole, including the black hole’s tidal potential, the disk’s Keplerian rotation, and orbital periods similar to those observed. After each disk encounter, freshly stripped stellar debris exits the Hill sphere to form an extended, asymmetric, roughly triaxial stream. Subsequent stream–disk collisions shock both stellar debris and disk gas to high specific energies and drive a wind-like outflow. At larger orbital periods the shocked stellar debris dominates the high specific energy debris, while at shorter periods the shocked disk energy can be similar. From the shocked stellar mass measured over time, we infer flare durations set by the stream–disk collision time, consistent with the observed constant duty cycle of ∼10%–20%, independent of orbital period. The total shocked debris energy is broadly consistent with QPE flare energetics at shorter orbital periods. Our results favor one observable flare per stellar orbit, except perhaps at the shortest periods where the shocked stellar and disk energetics can be similar. Variations in the stream’s center of mass relative to the star, its density, and other properties can produce diverse shifts in the flare’s peak relative to the star–disk collision. We discuss implications for QPE timing and other transients in galactic nuclei.
SN - 1538-4357
SN - 0004-637X
ER -