SIMBAD references

2017MNRAS.471.1888F - Mon. Not. R. Astron. Soc., 471, 1888-1891 (2017/October-3)

On the ancient field blue straggler HR 5455.

FUHRMANN K. and CHINI R.

Abstract (from CDS):

We report the discovery of HR 5455 as an ancient field blue straggler that upon Roche lobe overflow from its evolved companion, now a white dwarf, has been rejuvenated to a MBS = 1.32 ± 0.05 M☉ bright F6V source with a purported age of τ ≃ 1.7 Gyr. The unequivocal evidence for HR 5455 being instead a τ ≃ 12 Gyr old Population II star arises from its low iron-to-magnesium abundance ratio, and is supported by its kinematics, the lack of lithium and a companion mass MWD = 0.49 ± 0.09 M☉ from the P = 1086 ± 77 d Hipparcos astrometric orbit, which is in perfect agreement with the Rappaport et al. period-white dwarf mass relation. Like the F7V star 49 Lib that we recently disclosed as an ancient field blue straggler in a similar context, HR 5455 is also a very metal-rich source at [Mg/H] = +0.19 and [Fe/H] = -0.10. Unlike 49 Lib, however, only the white dwarf progenitor mass is directly constrained to MWD,progenitor = 1.06 ± 0.02 M☉. In case of a conservative mass transfer, which in analogy to the 49 Lib system appears likely, a blue straggler progenitor mass MBS,progenitor = 0.75 M☉ would follow.

Abstract Copyright: © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): blue stragglers - stars: fundamental parameters - stars: individual: HR 5455 - stars: Population II - stars: solar-type - white dwarfs - white dwarfs

Simbad objects: 9

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