Letter to the Editor
Separated before birth: pulsars B2020+28 and B2021+51 as the remnants of runaway stars
Sternberg Astronomical Institute, Moscow State University, Universitetskij Pr. 13, Moscow 119992, Russia e-mail: email@example.com
Accepted: 12 May 2007
Astrometric data on the pulsars B2020+28 and B2021+51 suggest that they originated within several parsecs of each other in the direction of the Cyg OB2 association. It was proposed that the pulsars share their origin in a common massive binary and were separated at the birth of the second pulsar following the asymmetric supernova explosion. We consider a different scenario for the origin of the pulsar pair based on a possibility that the pulsars were separated before their birth and that they are the remnants of runaway stars ejected (with velocities similar to those of the pulsars) from the core of Cyg OB2 due to strong three- or four-body dynamical encounters. Our scenario does not require any asymmetry in supernova explosions.
Key words: pulsars: individual: PSR B2020+28 / open clusters and associations: individual: PSR B2021+51
© ESO, 2007