2023ApJ...944L..39L


Query : 2023ApJ...944L..39L

2023ApJ...944L..39L - Astrophys. J., 944, L39 (2023/February-3)

Hypervelocity Stars Track Back to the Galactic Center in Gaia DR3.

LIAO J., DU C., LI H., MA J. and SHI J.

Abstract (from CDS):

Based on the proper motions and radial velocities from Gaia Data Release 3, we identify two hypervelocity stars (HVSs) that may originate from the Galactic center (GC). We select the candidates by first filtering for all Gaia stars with Galactocentric radial velocities >500 km s–1. We also require the candidates cross the Galactic midplane only once at 80% confidence, as determined by backwards orbit integration in several models of the Galactic potential, given the uncertainties in the Gaia measurables. The final two HVS candidates are the only such stars in our sample whose backwards-integrated trajectories pass within 1 kpc of the GC, suggesting a potential GC origin. We discuss possible ejection scenarios for these HVSs, in particular, by finding that ejection via the Hills mechanism is unlikely unless the HVS trajectories were significantly altered by local or large-scale perturbations to the assumed Galactic potential, e.g., the Large Magellanic Cloud. Interestingly, one of the HVSs ejects in a direction that is curiously aligned with the clockwise stellar disk around Sgr A*, suggesting a possible connection. We also discuss that the two stars may be ejected by other mechanisms.

Abstract Copyright: © 2023. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Hypervelocity stars - Stellar dynamics - Stellar kinematics - Galactic center - Supermassive black holes

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
2 Gaia DR3 6016819861087891456 HV* 16 30 39.0430835035 -41 27 59.477812193           ~ 2 0
3 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
4 [GEO97] W5 * 17 45 39.9696 -29 00 27.843           O9/9.5V 39 0
5 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4970 3
6 Gaia DR3 4094201527955913856 EB* 18 11 24.6058953091 -20 30 58.274403168           ~ 5 0
7 HE 2251-5127 HV* 22 54 51.6245437488 -51 11 44.195809848   16.0 16.1     ~ 45 0

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