Discovery of the nearby F6V star HR 3220 as a field blue straggler

Abstract

We report the discovery of the nearby single-lined and metal-poor F6V star HR 3220 as a field blue straggler from a basic inconsistency of the τ≃ 3Gyr evolutionary age compared to its low iron-to-magnesium abundance ratio which implies that HR 3220 must be instead as old as τ≃ 10Gyr. Our finding is corroborated by the observational constraints of the spectroscopic and astrometric P= 899d orbit, leading to a secondary mass MB≃ 0.42+0.09- 0.05 M⊙ that matches the Rappaport et al. period-white dwarf mass relation and the case of a mass transfer system. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.