A nearby recent supernova that ejected the runaway star ζ Oph, the pulsar PSR B1706−16, and 60Fe found on Earth

Abstract

ABSTRACT The detection of ∼1.5–3.2 Myr old 60Fe on Earth indicates recent nearby core-collapse supernovae. For supernovae in multiple stars, the primary stars may become neutron stars, while former companions may become unbound and become runaway stars. We wrote software for tracing back the space motion of runaway and neutron stars to young associations of massive stars. We apply it here to the nearby young Scorpius–Centaurus–Lupus groups, all known runaway stars possibly coming from there, and all 400 neutron stars with known transverse velocity. We find kinematic evidence that the runaway ζ Oph and the radio pulsar PSR B1706−16 were released by a supernova in a binary 1.78 ± 0.21 Myr ago at 107 ± 4 pc distance (for pulsar radial velocity 260 ± 43 km s−1); association age and flight time determine the progenitor mass (16–18 M⊙), which can constrain supernova nucleosynthesis yields and 60Fe uptake on Earth. In addition, we notice that the only high-mass X-ray binary in Scorpius–Centaurus–Lupus (1H11255−567 with μ1 and μ2 Cru) may include a neutron star formed in another SN, up to ∼1.8 Myr ago at 89−112 pc, i.e. also yielding 60Fe detectable on Earth. Our scenario links 60Fe found on Earth to one or two individual supernovae in multiple stars.