Neutron Star-Main-Sequence Star Collision: Formation and Long-Term Evolution of Thorne-Żytkow Objects
Abstract
Thorne-Żytkow objects (TŻOs) are stars containing a neutron-star (NS) or black-hole (BH) core embedded in a stellar envelope and powered primarily by mass accretion onto the core. Classical evolution models of TŻOs begin with an assumed equilibrium configuration and predict chemical anomalies in the stellar envelope resulting from nuclear burning in the vicinity of the NS core. Here we connect dynamical formation to long-term evolution by combining a three-dimensional simulation of a post-supernova collision between a 1.4M⊙ NS and a 10M⊙ main-sequence star with a subsequent stellar evolution calculation using MESA. The collision successfully produces a bound, quasi-spherical TŻO with the NS settled at the center of the stellar envelope. In contrast to the classical picture, the collision heats a substantial fraction of the star and leads to widespread nuclear burning during the subsequent thermal-relaxation phase. As the envelope becomes convective, material processed by the carbon-nitrogen cycle is transported to the surface, leaving a potentially observable chemical imprint of formation that persists after the star attains the standard accretion-supported TŻO structure. At the end of our simulation, the stellar luminosity greatly exceeds Eddington in the outer envelope, suggesting that significant mass ejection will occur, leaving behind an isolated NS or BH.
Related
- Hybrid neutron stars among mass gap objects are excluded by twin stars at 1.4 M⊙
- Investigating the formation of small Solar System objects using stellar occultations by satellites: present, future and its use to update satellite orbits
- Rotating Radio Transient Phases of Isolated Neutron Star Systems and Descendants of Central Compact Objects
- Two-Fluid Radial Stability of Dark-Matter-Admixed Compact Objects: Dark Compact Planets, Dark White Dwarfs, Dark Neutron Stars, and Dark Oysters
- Filament Formation via Collision-induced Magnetic Reconnection -- Kinematic Features
BibTeX
@misc{guo2026neutron,
title = {{Neutron Star-Main-Sequence Star Collision: Formation and Long-Term Evolution of Thorne-Żytkow Objects}},
author = {Yuhao Guo and Xiao-Tian Xu and Dong Lai},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.29833},
eprint = {2610.29833},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.29833},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Neutron Star-Main-Sequence Star Collision: Formation and Long-Term Evolution of Thorne-Żytkow Objects
AU - Yuhao Guo
AU - Xiao-Tian Xu
AU - Dong Lai
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.29833
UR - https://arxiv.org/abs/2610.29833
AB - Thorne-Żytkow objects (TŻOs) are stars containing a neutron-star (NS) or black-hole (BH) core embedded in a stellar envelope and powered primarily by mass accretion onto the core. Classical evolution models of TŻOs begin with an assumed equilibrium configuration and predict chemical anomalies in the stellar envelope resulting from nuclear burning in the vicinity of the NS core. Here we connect dynamical formation to long-term evolution by combining a three-dimensional simulation of a post-supernova collision between a 1.4M_⊙ NS and a 10M_⊙ main-sequence star with a subsequent stellar evolution calculation using MESA. The collision successfully produces a bound, quasi-spherical TŻO with the NS settled at the center of the stellar envelope. In contrast to the classical picture, the collision heats a substantial fraction of the star and leads to widespread nuclear burning during the subsequent thermal-relaxation phase. As the envelope becomes convective, material processed by the carbon-nitrogen cycle is transported to the surface, leaving a potentially observable chemical imprint of formation that persists after the star attains the standard accretion-supported TŻO structure. At the end of our simulation, the stellar luminosity greatly exceeds Eddington in the outer envelope, suggesting that significant mass ejection will occur, leaving behind an isolated NS or BH.
ER -