Could the number of blue straggler stars help to determine the age of their parent globular cluster?

Volume 5, Issue 2, April 2023     |     PP. 29-41      |     PDF (511 K)    |     Pub. Date: August 22, 2023
DOI: 10.54647/astronomy160048    76 Downloads     1252 Views  

Author(s)

Félix Llorente de Andrés, Centro de Astrobiología (CAB), CSIC-INTA, Camino Bajo del Castillo s/n, campus ESAC, 28692, Villanueva de la Cañada, Madrid, Spain; Ateneo de Almagro, Sección de Ciencia y Tecnología, 13270 Almagro, Spain

Abstract
A recent study shows, from an empirical deduction, that the number and the presence of the blue straggler stars (BSS) in an open cluster follow a function whose components are the ratio between age and the relaxation time, ƒ, and a factor, ϖ, which is an indicator of stellar collisions plus primordial binaries. The relation among the number of blue straggler stars, the factor ƒ and the factor ϖ of each globular cluster allows for deriving the age of the respective globular clusters. This method has been applied individually over 56 globular clusters containing BSS. The values derived for the cluster ages from our methodology do not differ from those derived from other methods. A special case is the cluster NGC104 whose age exceeds 13.8 Gyr (its age is in between 19.04 and 20.30Gyr), which would have a very exotic explanation: the existence of an intermediate black hole in the center of the cluster. That black hole main-sequence star (BH-MS) binaries with an initial orbital period less than the bifurcation period can evolve into ultra-compact X-ray binaries (UCXBs) that can be detected by LISA. On the other hand, if that age were true, it would call into question the expansion velcity for a flat Universe. This would call into question the case for a dark energy–dominated Universe.

Keywords
galaxy: globular clusters: general –stars: blue stragglers

Cite this paper
Félix Llorente de Andrés, Could the number of blue straggler stars help to determine the age of their parent globular cluster? , SCIREA Journal of Astronomy. Volume 5, Issue 2, April 2023 | PP. 29-41. 10.54647/astronomy160048

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