On the origin of the O and B-type stars with high velocities II. Runaway stars and pulsars ejected from the nearby young stellar groups

We use milli-arcsecond accuracy astrometry (proper motions and parallaxes) from Hipparcos and from radio observations to retrace the orbits of 56 runa way stars and nine compact objects with distances less than 700 pc, to iden tify the parent stellar group. It is possible to deduce the specific format ion scenario with near certainty for two cases. (i) We find that the runawa y star zeta Ophiuchi and the pulsar PSR 51932+1059 originated about 1 Myr a go in a supernova explosion in a binary in the Upper Scorpius subgroup of t he Sco OB2 association. The pulsar received a kick velocity of similar to 3 50 km s(-1) in this event, which dissociated the binary, and gave zeta Oph its large space velocity. (ii) Blaauw & Morgan and Gies & Bolton already po stulated a common origin for the runaway-pair AE Aur and mu Col, possibly i nvolving the massive highly-eccentric binary iota Ori, based on their equal and opposite velocities. We demonstrate that these three objects indeed oc cupied a very small volume similar to2.5 Myr ago, and show that they were e jected from the nascent Trapezium cluster. We identify the parent group for two more pulsars: both likely originate in the similar to 50 Myr old assoc iation Per OB3, which contains the open cluster alpha Persei. At least 21 o f the 56 runaway stars in our sample can be linked to the nearby associatio ns and young open clusters. These include the classical runaways 53 Arietis (Ori OB1), xi Persei (Per OB2), and lambda Cephei (Cep OB3), and fifteen n ew identifications, amongst which a pair of stars running away in opposite directions from the region containing the lambda Ori cluster. Other current ly nearby runaways and pulsars originated beyond 700 pc, where our knowledg e of the parent groups is very incomplete.