A solution to the paradox of youth in the Galactic centre

@misc{silva2026solution,
  title = {{A solution to the paradox of youth in the Galactic centre}},
  author = {Rodrigo P. Silva and Alexandre C. M. Correia and Tjarda C. N. Boekholt and Paulo J. V. Garcia},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.31305},
  eprint = {2609.31305},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.31305},
}

TY  - UNPB
TI  - A solution to the paradox of youth in the Galactic centre
AU  - Rodrigo P. Silva
AU  - Alexandre C. M. Correia
AU  - Tjarda C. N. Boekholt
AU  - Paulo J. V. Garcia
PY  - 2026
DA  - 2026/09/25
PB  - arXiv
DO  - 10.48550/arxiv.2609.31305
UR  - https://arxiv.org/abs/2609.31305
AB  - The supermassive black hole at the Galactic centre, Sgr A*, is surrounded by an S cluster of young stars. These stars are predominantly B-type stars, but their origin remains uncertain. Unlike massive stars in the Galactic field, which exhibit a binary fraction of about 70%, those in the S cluster show a significantly lower fraction. It is key to understand this discrepancy for constraining their formation. We show that the binary deficit arises naturally from dynamical interactions between stellar binaries and Sgr A* in an in situ formation scenario. Using K-amplitude data, we derived an observational binary fraction of f_obs = 0.43 ± 0.09 for the S-cluster stars. Our dynamical modelling predicts that interactions with Sgr A* cause 18% of the binaries to merge, 20% to be disrupted, and 62% to survive, yielding a theoretical binary fraction of f_theo = 0.38 ± 0.10. The predicted binary fraction with distance from Sgr A* is also consistent with independent observational constraints. These results show that the decline in binarity towards the Galactic centre is driven by stronger tidal forces, and they support an in situ origin of the S cluster in the same event that produced the Fermi bubbles.
ER  -