# Importance of stable mass transfer and stellar winds for the formation of gravitational wave sources

**Authors:** Andris Dorozsmai, Silvia Toonen  
**arXiv:** [2207.08837](https://arxiv.org/abs/2207.08837)  
**Date:** 2022-07-18  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2207.08837v1/

## Key points

- Gravitational wave (GW) detections provide insights into merging black hole binaries
- Formation mechanisms of these binaries are still debated
- Study focuses on classical isolated binary formation channel
- Population synthesis code SeBa used for parameter study
- Uncertainties explored include mass transfer efficiency, angular momentum loss, stability criteria for mass transfer, effective temperature for convective envelope development, and stellar winds
- Results show complex effects of parameters on GW source population properties
- Mass transfer stability criteria impact depends on assumed efficiency
- Uncertainties in angular momentum loss affect relative rates between dominant channels
- Direct inference from gravitational data alone not recommended due to uncertainties and lack of reliable models
- Understanding sensitivity of coalescing binary black hole populations to astrophysical parameters is crucial for accurate interpretation of gravitational wave observations
- Stable mass transfer and stellar winds important in shaping formation and properties of GW sources
- Further investigations with refined models and reduced uncertainties needed for deeper insights into massive binary evolution through GW data analysis.

## Summary

The large number of gravitational wave (GW) detections have provided valuable insights into the properties of merging black hole binaries. However, the formation mechanisms of these binaries are still a subject of intense debate. To better understand the impact of stellar physics on the observable GW population and to constrain the poorly understood evolution of massive binaries, this study focuses on the classical isolated binary formation channel. Using the population synthesis code SeBa, the authors perform a comprehensive parameter study that explores uncertainties related to stable mass transfer phases and stellar winds. The simulations cover a wide range of metallicities to account for variations in stellar composition. Five key assumptions are varied: 1) mass transfer efficiency during the first mass transfer phase, 2) angular momentum loss during mass transfer, 3) stability criteria for mass transfer from giant donors with radiative envelopes, 4) effective temperature at which an evolved star develops a deep convective envelope, and 5) stellar winds. The results reveal complex and interrelated effects of these parameters on the population properties of GW sources. Notably, it is shown that the impact of the mass transfer stability criteria depends on the assumed mass transfer efficiency. Additionally, uncertainties in angular momentum loss significantly affect the relative rates between two dominant channels. However, due to numerous uncertainties and lack of reliable models in current astrophysics research, direct inference from gravitational data alone is not recommended at this stage. Nonetheless, understanding how sensitive coalescing binary black hole populations are to various astrophysical parameters is crucial for interpreting gravitational wave observations accurately. In conclusion, this study highlights the importance of stable mass transfer and stellar winds in shaping both formation and properties of gravitational wave sources. Further investigations incorporating more refined models and reducing uncertainties will be essential for gaining deeper insights into massive binary evolution through gravitational wave data analysis.