Spatial mixing of stellar populations in globular clusters via binary-single star scattering

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00643349" target="_blank" >RIV/67985815:_____/25:00643349 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0373302" target="_blank" >https://hdl.handle.net/11104/0373302</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202556753" target="_blank" >10.1051/0004-6361/202556753</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Spatial mixing of stellar populations in globular clusters via binary-single star scattering

Popis výsledku v původním jazyce

Context. The majority of Galactic globular star clusters (GCs) have been reported to contain at least two populations of stars (hereafter, we use P1 for the primordial and P2 for the chemically enriched population). Recent observational studies found that dynamically old GCs have P1 and P2 spatially mixed due to relaxation processes. However, in dynamically young GCs, where P2 is expected to be more centrally concentrated from birth, the spatial distributions of P1 and P2 are sometimes very different from system to system. This suggests that more complex dynamical processes specific to certain GCs might have shaped those distributions. Aims. We aim to investigate the discrepancies between the spatial concentration of P1 and P2 stars in dynamically young GCs. Our main focus is to evaluate whether massive binary stars (e.g. black holes) can cause the expansion of the P2 stars through binary-single interactions in the core, and whether they can mix or even radially invert the P1 and P2 distributions. Methods. We use a set of theoretical and empirical arguments to evaluate the effectiveness of binary-single star scattering. We then construct a set of direct N-body models with massive primordial binaries to verify our estimates further and gain more insights into the dynamical processes in GCs. Results. We find that binary-single star scatterings can push the central P2 stars outwards within a few relaxation times. While we do not produce radial inversion of P1 and P2 for any initial conditions we tested, this mechanism systematically produces clusters where P1 and P2 look fully mixed even in projection. The mixing is enhanced (1) in denser GCs, (2) in GCs containing more binary stars, and (3) when the mass ratio between the binary components and the cluster members is higher. Conclusions. Binary-single star interactions seem able to explain the observable properties of some dynamically young GCs (e.g. NGC 4590 or NGC 5904) where P1 and P2 are fully radially mixed.

Název v anglickém jazyce

Spatial mixing of stellar populations in globular clusters via binary-single star scattering

Popis výsledku anglicky

Context. The majority of Galactic globular star clusters (GCs) have been reported to contain at least two populations of stars (hereafter, we use P1 for the primordial and P2 for the chemically enriched population). Recent observational studies found that dynamically old GCs have P1 and P2 spatially mixed due to relaxation processes. However, in dynamically young GCs, where P2 is expected to be more centrally concentrated from birth, the spatial distributions of P1 and P2 are sometimes very different from system to system. This suggests that more complex dynamical processes specific to certain GCs might have shaped those distributions. Aims. We aim to investigate the discrepancies between the spatial concentration of P1 and P2 stars in dynamically young GCs. Our main focus is to evaluate whether massive binary stars (e.g. black holes) can cause the expansion of the P2 stars through binary-single interactions in the core, and whether they can mix or even radially invert the P1 and P2 distributions. Methods. We use a set of theoretical and empirical arguments to evaluate the effectiveness of binary-single star scattering. We then construct a set of direct N-body models with massive primordial binaries to verify our estimates further and gain more insights into the dynamical processes in GCs. Results. We find that binary-single star scatterings can push the central P2 stars outwards within a few relaxation times. While we do not produce radial inversion of P1 and P2 for any initial conditions we tested, this mechanism systematically produces clusters where P1 and P2 look fully mixed even in projection. The mixing is enhanced (1) in denser GCs, (2) in GCs containing more binary stars, and (3) when the mass ratio between the binary components and the cluster members is higher. Conclusions. Binary-single star interactions seem able to explain the observable properties of some dynamically young GCs (e.g. NGC 4590 or NGC 5904) where P1 and P2 are fully radially mixed.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

703

Číslo periodika v rámci svazku

Nov.

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

12

Strana od-do

A157

Kód UT WoS článku

001626464600015

EID výsledku v databázi Scopus

2-s2.0-105021855349