Open Clusters IC 4665 and Cr 359 and a Probable Birthplace of the Pulsar PSR B1929+10

TL;DR

This study simulates the past motions of open clusters IC 4665 and Cr 359, revealing their historical proximity, potential connection to the Scorpius-Centaurus association, and a candidate binary partner for pulsar PSR B1929+10.

Contribution

It introduces a new epicyclic approximation-based simulation of cluster motions, linking clusters to local structures and identifying potential pulsar binary origins.

Findings

IC 4665 and Cr 359 were closest 7 Myr ago, 36 pc apart.

IC 4665 was near the Local Bubble and North Polar Spur 15 Myr ago.

HIP 86768 may have been a binary companion to PSR B1929+10.

Abstract

Based on the epicyclic approximation, we have simulated the motion of the young open star clusters IC 4665 and Collinder 359. The separation between the cluster centers is shown to have been minimal 7 Myr ago, 36 pc. We have established a close evolutionary connection between IC 4665 and the Scorpius-Centaurus association -- the separation between the centers of these structures was $\approx200$ pc 15 Myr ago. In addition, the center of IC 4665 at this time was near two well-known regions of coronal gas: the Local Bubble and the North Polar Spur. The star HIP 86768 is shown to be one of the candidates for a binary (in the past) with the pulsar PSR B1929+10. At the model radial velocity of the pulsar $V_r= 2\pm50$ km s$^{-1}$, a close encounter of this pair occurs in the vicinity of IC 4665 at a time of -1.1 Myr. At the same time, using currently available data for the pulsar B1929+10 at its model radial velocity $V_r=200\pm50$ km s$^{-1}$, we show that the hypothesis of Hoogerwerf et al. (2001) about the breakup of the $\zeta$Oph--B1929+10 binary in the vicinity of Upper Scorpius (US) about 0.9 Myr ago is more plausible.