N-enhancement in GN-z11: First evidence for supermassive stars nucleosynthesis in proto-globular clusters-like conditions at high redshift?
Abstract
Unusually high N/O abundance ratios were recently reported for a very compact, intensively star-forming object GN-z11 at z = 10.6 from JWST/NIRSpec observations. We present an empirical comparison with the C, N, and O abundance ratios in Galactic globular clusters (GCs) over a large metallicity range. We show that hot hydrogen-burning nucleosynthesis within supermassive stars (SMS) formed through runaway collisions can consistently explain the observed abundances ratio in GN-z11 and in GCs. This suggests that a proto-globular cluster hosting a SMS could be at the origin of the strong N-enrichment in GN-z11. Our model predicts the behavior of N/O, C/O, and Ne/O ratios as a function of metallicity, which can be tested if high-z objects similar to GN-z11 are detected with JWST in the future. Further studies and statistics will help differentiate the proto-GC scenario from the Wolf-Rayet scenario that we quantify with a population synthesis model, and shed more light on this peculiar object.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- May 2023
- DOI:
- arXiv:
- arXiv:2303.07955
- Bibcode:
- 2023A&A...673L...7C
- Keywords:
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- galaxies: high-redshift;
- galaxies: ISM;
- galaxies: abundances;
- galaxies: star clusters: general;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted by A&