Revisiting the Evolutionary Status of Massive Stars at the central parsec of the Milky Way
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arXiv
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2025
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| author | Gormaz-Matamala, A. C. Cuadra, J. Kubátová, B. Kubát, J. Ekström, S. |
| author_facet | Gormaz-Matamala, A. C. Cuadra, J. Kubátová, B. Kubát, J. Ekström, S. |
| contents | Massive stars and their winds have a large influence in their environment, e.g, determining the accretion rate on to the Galactic Centre (GC) super-massive black hole Sgr A*. The winds of those stars collide and are accreted, at a rate that depends on their chemical composition. Here we aim to revisit the evolutionary status of the evolved massive stars at the GC, by means of new tracks based on updated mass-loss rate recipes for the earlier stages of massive stars.
We use the Geneva-evolution-code for initial stellar masses ranging from 20 to 60 $M_\odot$, for metallicity $Z=0.020$. We adopt a new mass-loss rate recipe for the line-driven winds of O-type stars and B-supergiants, plus a new recipe for the dust-driven winds of red supergiants (RSG). Additionally, we set up initial rotation $Ω/Ω_\text{crit}=0.4$, and we adopt the Ledoux criterion for the treatment of convection in inner layers.
We found that evolution models adopting new mass-loss rate prescriptions predict that stars will lose less of their outer layers during their initial phases, while a big reduction of mass happens at the RSG phase. As a consequence, the resulting Wolf-Rayet (WR) stars are less radially homogeneous in their inner structure from the core to the surface. Also, these new evolution models predict the absence of hydrogen-free WN stars. These evolutionary predictions agree better with the observed chemical abundances of the WR stars at the GC.
We provide a table with the chemical H, He, and CNO abundances calculated for the different subtypes of WR stars. We propose a different re-arrangement of the WR subtypes to be used for the modelling of the collision of their winds. We discuss the potential implications of these changes for the colliding winds generated from the massive stars at the GC, which are accreting onto the supermassive black hole Sgr A*. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_07432 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Revisiting the Evolutionary Status of Massive Stars at the central parsec of the Milky Way Gormaz-Matamala, A. C. Cuadra, J. Kubátová, B. Kubát, J. Ekström, S. Solar and Stellar Astrophysics Astrophysics of Galaxies Massive stars and their winds have a large influence in their environment, e.g, determining the accretion rate on to the Galactic Centre (GC) super-massive black hole Sgr A*. The winds of those stars collide and are accreted, at a rate that depends on their chemical composition. Here we aim to revisit the evolutionary status of the evolved massive stars at the GC, by means of new tracks based on updated mass-loss rate recipes for the earlier stages of massive stars. We use the Geneva-evolution-code for initial stellar masses ranging from 20 to 60 $M_\odot$, for metallicity $Z=0.020$. We adopt a new mass-loss rate recipe for the line-driven winds of O-type stars and B-supergiants, plus a new recipe for the dust-driven winds of red supergiants (RSG). Additionally, we set up initial rotation $Ω/Ω_\text{crit}=0.4$, and we adopt the Ledoux criterion for the treatment of convection in inner layers. We found that evolution models adopting new mass-loss rate prescriptions predict that stars will lose less of their outer layers during their initial phases, while a big reduction of mass happens at the RSG phase. As a consequence, the resulting Wolf-Rayet (WR) stars are less radially homogeneous in their inner structure from the core to the surface. Also, these new evolution models predict the absence of hydrogen-free WN stars. These evolutionary predictions agree better with the observed chemical abundances of the WR stars at the GC. We provide a table with the chemical H, He, and CNO abundances calculated for the different subtypes of WR stars. We propose a different re-arrangement of the WR subtypes to be used for the modelling of the collision of their winds. We discuss the potential implications of these changes for the colliding winds generated from the massive stars at the GC, which are accreting onto the supermassive black hole Sgr A*. |
| title | Revisiting the Evolutionary Status of Massive Stars at the central parsec of the Milky Way |
| topic | Solar and Stellar Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2512.07432 |