SIMBAD references

2018ApJ...866..121H - Astrophys. J., 866, 121-121 (2018/October-3)

Old, metal-poor extreme velocity stars in the solar neighborhood.


Abstract (from CDS):

We report the discovery of 30 stars with extreme space velocities (>=480 kms–1) in the Gaia-DR2 archive. These stars are a subset of 1743 stars with high-precision parallax, large tangential velocity (vtan > 300 kms–1), and measured line-of-sight velocity in DR2. By tracing the orbits of the stars back in time, we find at least one of them is consistent with having been ejected by the supermassive black hole at the Galactic Center. Another star has an orbit that passed near the Large Magellanic Cloud about 200 Myr ago. Unlike previously discovered blue hypervelocity stars, our sample is metal-poor (-1.5 < [Fe/H] < -1.0) and quite old (>1 Gyr). We discuss possible mechanisms for accelerating old stars to such extreme velocities. The high observed space density of this population, relative to potential acceleration mechanisms, implies that these stars are probably bound to the Milky Way (MW). If they are bound, the discovery of this population would require a local escape speed of around ∼600 kms–1 and consequently imply a virial mass of M200 ∼ 1.4 x 1012M for the MW.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

Journal keyword(s): Galaxy: fundamental parameters - Galaxy: halo - Galaxy: kinematics and dynamics - Magellanic Clouds - stars: kinematics and dynamics

CDS comments: In table 1 the "Short Names" like Gaia-T-ESNN will not be added in Simbad. Please use the official format for Gaia DR2 identifiers.

Simbad objects: 39

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