Issue |
A&A
Volume 693, January 2025
|
|
---|---|---|
Article Number | A37 | |
Number of page(s) | 11 | |
Section | Galactic structure, stellar clusters and populations | |
DOI | https://doi.org/10.1051/0004-6361/202451630 | |
Published online | 24 December 2024 |
Tracing the Milky Way spiral arms with 26Al
The role of nova systems in the 2D distribution of 26Al
1
Dipartimento di Fisica, Sezione di Astronomia, Università di Trieste,
Via G. B. Tiepolo 11,
34143
Trieste,
Italy
2
I.N.A.F. Osservatorio Astronomico di Trieste,
via G.B. Tiepolo 11,
34131
Trieste,
Italy
3
I.N.F.N. Sezione di Trieste,
via Valerio 2,
34134
Trieste,
Italy
4
INAF – Osservatorio Astronomico di Capodimonte,
Salita Moiariello 16,
80131
Napoli,
Italy
5
ICRANet,
Piazza della Repubblica 10,
65122
Pescara,
Italy
★ Corresponding author; arianna.vasini@inaf.it
Received:
23
July
2024
Accepted:
11
November
2024
Context. Massive stars are one of the most important and investigated astrophysical production sites of 26Al, a short-lived radioisotope with an ~1 Myr half-life. Its short lifetime prevents us from observing its complete chemical history, and only the 26Al that was recently produced by massive stars can be observed. Hence, it is considered a tracer of star formation rate (SFR). However, important contributions to 26Al come from nova systems that pollute the interstellar medium with a large delay, thus partly erasing the correlation between 26Al and SFR.
Aims. In this work, we aim to describe the 2D distribution of the mass of 26Al as well as that of massive stars and nova systems in the Milky Way (MW), to investigate their relative contributions to the production of 26Al.
Methods. We used a detailed 2D chemical evolution model where the SFR is azimuthally dependent and is required to reproduce the spiral arm pattern observed in the MW. We tested two different models, one where the 26Al comes from massive stars and novae, and one with massive stars only. We then compared the predictions to the ~2 M⊙ of 26Al mass observed by the surveys of the Compton Telescope (COMPTEL) and International Gamma-Ray Laboratory (INTEGRAI).
Results. The results show that novae do not trace SFR and, in the solar vicinity, they concentrate in its minima. The effect of novae on the map of the 26Al mass consists in damping the spiral pattern by a factor of five. Regarding the nucleosynthesis, we find that ~75% of the 26Al is produced by novae and the ~25% by massive stars.
Conclusions. We conclude that novae cannot be neglected as 26Al producers since the observations can only be reproduced by including their contribution. Moreover, we suggest that bulge novae should eject around six times more material than the disc ones to well reproduce the observed mass of 26Al.
Key words: novae, cataclysmic variables / Galaxy: abundances / Galaxy: bulge / Galaxy: disk / Galaxy: evolution / gamma rays: diffuse background
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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