Description
The majority of the massive OB-type stars (M $\geq$ $8M\odot$) are found in OB associations confined to the Galactic plane. Most of these massive stars are in binaries. If the binary is tight enough, a phase of mass transfer occurs when the initially most massive star (the primary) expands and fills its Roche lobe. As a consequence, the mass ratio inverts and the secondary becomes the most massive star in the binary system. Under these conditions the system may remain bound when the primary goes supernova. The compact remnant of the primary, a neutron star or a black hole, becomes observable as an X-ray source if the stellar wind of the companion OB star is intercepted or if a second phase of Roche-lobe overflow commences. During this relatively short phase in the evolution of a massive binary, the system is called a high-mass X-ray binary (HMXB). Due to the mass loss from the system during the supernova explosion, the system gets a recoil velocity of the order of the orbital velocity of the exploding star before the supernova. An additional kick is asserted onto the system if the supernova explosion is asymmetric. The kick ejects the binary system from its parent OB association while they remain bound together thus, HMXBs are predicted to be runaway systems, i.e. they are running away from their birth location: the parent OB association. With Gaia’s high precision astrometry we have the unique opportunity to study the kinematics of HMXBs and to reconstruct the evolutionary history of the binary system. With Gaia DR3 we determine the runaway velocity and the Galactic paths of 121 HMXBs, taking into account the Galactic potential. With the Galactic path we may identify a parent cluster and reconstruct the motion of the HMXB with respect to its parent cluster and determine its kinematic age; the age at which the HMXB was ejected from the cluster. With the kinematic age and the cluster age we constraint the evolutionary history of the HMXB.
| Talk category | NOVA Network 2 |
|---|---|
| Preference for a talk or poster | Poster |
