A binary-related origin mediated by environmental conditions for blue straggler stars

Fuente: arXiv
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Hauptverfasser: Ferraro, Francesco R., Lanzoni, Barbara, Vesperini, Enrico, Dalessandro, Emanuele, Cadelano, Mario, Pallanca, Cristina, Beccari, Giacomo, Nardiello, Domenico, Libralato, Mattia, Piotto, Giampaolo
Format: Preprint
Veröffentlicht: 2025
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author Ferraro, Francesco R.
Lanzoni, Barbara
Vesperini, Enrico
Dalessandro, Emanuele
Cadelano, Mario
Pallanca, Cristina
Beccari, Giacomo
Nardiello, Domenico
Libralato, Mattia
Piotto, Giampaolo
author_facet Ferraro, Francesco R.
Lanzoni, Barbara
Vesperini, Enrico
Dalessandro, Emanuele
Cadelano, Mario
Pallanca, Cristina
Beccari, Giacomo
Nardiello, Domenico
Libralato, Mattia
Piotto, Giampaolo
contents Blue stragglers are anomalously massive core hydrogen-burning stars that, according to the theory of single star evolution, should not exist. They are suspected to form in mass-enhancement processes, involving binary evolution or stellar collisions. In dynamically active systems like globular clusters, the number of blue stragglers originated by collisions is expected to increase with the local density and the rate of stellar encounters. Here we analyse more than 3000 blue stragglers in 48 Galactic globular clusters with different structures, finding that their number normalized to the sampled luminosity anti-correlates (instead of correlating) with the central density, collision rate, and dynamical age of the parent cluster. Similar trends are also found for the cluster binary fraction. Once inserted in the context of the current knowledge of the BSS phenomenon, these correlations indicate that low-density regions (possibly because of a higher binary production/survival rate) are the natural habitat of both BSSs and binary systems, and the observed BSSs mostly have a binary-related origin mediated by the environmental conditions.
format Preprint
id arxiv_https___arxiv_org_abs_2506_07692
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A binary-related origin mediated by environmental conditions for blue straggler stars
Ferraro, Francesco R.
Lanzoni, Barbara
Vesperini, Enrico
Dalessandro, Emanuele
Cadelano, Mario
Pallanca, Cristina
Beccari, Giacomo
Nardiello, Domenico
Libralato, Mattia
Piotto, Giampaolo
Solar and Stellar Astrophysics
Astrophysics of Galaxies
Blue stragglers are anomalously massive core hydrogen-burning stars that, according to the theory of single star evolution, should not exist. They are suspected to form in mass-enhancement processes, involving binary evolution or stellar collisions. In dynamically active systems like globular clusters, the number of blue stragglers originated by collisions is expected to increase with the local density and the rate of stellar encounters. Here we analyse more than 3000 blue stragglers in 48 Galactic globular clusters with different structures, finding that their number normalized to the sampled luminosity anti-correlates (instead of correlating) with the central density, collision rate, and dynamical age of the parent cluster. Similar trends are also found for the cluster binary fraction. Once inserted in the context of the current knowledge of the BSS phenomenon, these correlations indicate that low-density regions (possibly because of a higher binary production/survival rate) are the natural habitat of both BSSs and binary systems, and the observed BSSs mostly have a binary-related origin mediated by the environmental conditions.
title A binary-related origin mediated by environmental conditions for blue straggler stars
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2506.07692