Related papers: PG 1610$+$062: a runaway B star challenging classi…

Runaway stars are stars observed to have large peculiar velocities. Two mechanisms are thought to contribute to the ejection of runaway stars, both involve binarity (or higher multiplicity). In the binary supernova scenario a runaway star…

There are two accepted mechanisms to explain the origin of runaway OB-type stars: the Binary Supernova Scenario (BSS), and the Cluster Ejection Scenario (CES). In the former, a supernova explosion within a close binary ejects the secondary…

The dwarf carbon (dC) star SDSS J112801.67+004034.6 has an unusually high radial velocity, 531$\pm 4$ km s$^{-1}$. We present proper motion and new spectroscopic observations which imply a large Galactic rest frame velocity, 425$\pm 9$ km…

We have discovered a star, SDSS J090745.0+024507, leaving the Galaxy with a heliocentric radial velocity of +853+-12 km/s, the largest velocity ever observed in the Milky Way halo. The star is either a hot blue horizontal branch star or a…

In the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during…

We describe new optical photometric and spectroscopic observations of the semi-detached eclipsing binary BG Geminorum. A large change in the amount of Mg I absorption at secondary maximum indicates the presence of cool material in the outer…

Recent proper motion and parallax measurements for the pulsar PSR B1508+55 indicate a transverse velocity of ~1100 km/s, which exceeds earlier measurements for any neutron star. The spin-down characteristics of PSR B1508+55 are typical for…

Hypervelocity stars are believed to be ejected out from the Galactic center through dynamical interactions of (binary) stars with the central massive black hole(s). In this letter, we report 13 metal-poor F-type hypervelocity star…

We investigate the nature of nearby (10-15 kpc) high-speed stars in the Gaia DR2 archive identified on the basis of parallax, proper motion and radial velocity. Together with a consideration of their kinematic, orbital, and photometric…

A relevant fraction of massive stars are runaway stars. These stars move with a significant peculiar velocity with respect to their environment. We aim to discover and characterize the population of massive and early-type runaway stars in…

PG 1002+506 is found to be a Be star, one of two so far found by the Palomar-Green survey. Its spectrum is classified as a B5 +/- 1 Ve, with Teff = 14,900 +/- 1200, log g = 4.2 +/- 0.2, and v sin i = 340 +/- 50 km/s. At b = +51 degrees, its…

In recent years surveys have identified several dozen B stars in the Milky Way halo moving faster than the local escape speed. The origin of most of these hypervelocity stars (HVSs) is still poorly constrained. Here we show that the…

Our Galactic center contains young stars, including the few million year old clockwise disk between 0.05 and 0.5 pc from the Galactic center, and the S-star cluster of B-type stars at a galactocentric distance of ~0.01 pc. Recent…

Several dozen hypervelocity star (HVS) candidates have been reported based on the second data release of Gaia (Gaia DR2). However, it has been proven that the radial velocities of some Gaia HVS candidates are not reliable. In this paper, we…

Hills (1988) predicted that runaway stars could be accelerated to velocities larger than 1000 km/s by dynamical encounters with the supermassive black hole (SMBH) in the Galactic center. The recently discovered hypervelocity star SDSS…

We perform binary population synthesis calculations to study the origin and the characteristics of runaway O and B stars which are ejected by the supernova explosion of the companion star in a binary system. The number of OB runaways can be…

Using the recently determined spatial velocity components of the extreme runaway star HIP 60350 and a gravitation potential model of the Galaxy, we integrate the orbit of HIP 60350 back to the plane of the Galaxy. In this way, a possible…

We report the discovery of high velocity candidates among RR~Lyrae stars found in the Milky Way halo. We identified 9 RR~Lyrae stars with Galactocentric velocities exceeding the local escape velocity based on the assumed Galaxy potential.…

We report the detection of five high-velocity stars in the core of the globular cluster NGC 2808. The stars lie on the the red giant branch and show total velocities between 40 and 45 km/s. For a core velocity dispersion sigma_c = 13.4…

We report the discovery of a nearby star with a very large proper motion of 5.06 +/- 0.03 arcsec/yr. The star is called SO025300.5+165258 and referred to herein as HPMS (high proper motion star). The discovery came as a result of a search…