The enormous velocities of the so-called hypervelocity stars (HVSs) derive, likely, from close interactions with massive black holes, binary stars encounters or supernova explosions. In this paper, we investigate the origin of HVSs as consequence of the close interaction between the Milky Way central massive black hole and a passing-by young stellar cluster. We found that both single and binary HVSs may be generated in a burst-like event, as the cluster passes near the orbital pericentre. High-velocity stars will move close to the initial cluster orbital plane and in the direction of the cluster orbital motion at the pericentre. The binary fraction of these HVS jets depends on the primordial binary fraction in the young cluster. The level of initial mass segregation determines the value of the average mass of the ejected stars. Some binary stars will merge, continuing their travel across and out of the Galaxy as blue stragglers.

Hypervelocity stars from young stellar clusters in the Galactic Centre / Fragione, Giacomo; CAPUZZO DOLCETTA, Roberto Angelo; Kroupa, P.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - STAMPA. - 467:(2017), pp. 451-460. [10.1093/mnras/stx106]

Hypervelocity stars from young stellar clusters in the Galactic Centre

FRAGIONE, GIACOMO;CAPUZZO DOLCETTA, Roberto Angelo;
2017

Abstract

The enormous velocities of the so-called hypervelocity stars (HVSs) derive, likely, from close interactions with massive black holes, binary stars encounters or supernova explosions. In this paper, we investigate the origin of HVSs as consequence of the close interaction between the Milky Way central massive black hole and a passing-by young stellar cluster. We found that both single and binary HVSs may be generated in a burst-like event, as the cluster passes near the orbital pericentre. High-velocity stars will move close to the initial cluster orbital plane and in the direction of the cluster orbital motion at the pericentre. The binary fraction of these HVS jets depends on the primordial binary fraction in the young cluster. The level of initial mass segregation determines the value of the average mass of the ejected stars. Some binary stars will merge, continuing their travel across and out of the Galaxy as blue stragglers.
2017
stars: kinematics and dynamics; Galaxy: centre; Galaxy: kinematics and dynamics; galaxies: star clusters: general
01 Pubblicazione su rivista::01a Articolo in rivista
Hypervelocity stars from young stellar clusters in the Galactic Centre / Fragione, Giacomo; CAPUZZO DOLCETTA, Roberto Angelo; Kroupa, P.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - STAMPA. - 467:(2017), pp. 451-460. [10.1093/mnras/stx106]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/961774
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