Hawkins, K;
Kordopatis, G;
Gilmore, G;
Masseron, T;
Wyse, RFG;
Ruchti, G;
Bienayme, O;
... Zwitter, T; + view all
(2015)
Characterizing the high-velocity stars of RAVE: the discovery of a metal-rich halo star born in the Galactic disc.
Monthly Notices of the Royal Astronomical Society
, 447
(2)
pp. 2046-2058.
10.1093/mnras/stu2574.
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Abstract
We aim to characterize high-velocity (HiVel) stars in the solar vicinity both chemically and kinematically using the fourth data release of the RAdial Velocity Experiment (RAVE). We used a sample of 57 HiVel stars with Galactic rest-frame velocities larger than 275 km s−1. With 6D position and velocity information, we integrated the orbits of the HiVel stars and found that, on average, they reach out to 13 kpc from the Galactic plane and have relatively eccentric orbits consistent with the Galactic halo. Using the stellar parameters and [α/Fe] estimates from RAVE, we found the metallicity distribution of the HiVel stars peak at [M/H] = −1.2 dex and is chemically consistent with the inner halo. There are a few notable exceptions that include a hypervelocity star candidate, an extremely HiVel bound halo star, and one star that is kinematically consistent with the halo but chemically consistent with the disc. High-resolution spectra were obtained for the metal-rich HiVel star candidate and the second highest velocity star in the sample. Using these high-resolution data, we report the discovery of a metal-rich halo star that has likely been dynamically ejected into the halo from the Galactic thick disc. This discovery could aid in explaining the assembly of the most metal-rich component of the Galactic halo.
| Type: | Article |
|---|---|
| Title: | Characterizing the high-velocity stars of RAVE: the discovery of a metal-rich halo star born in the Galactic disc |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stu2574 |
| Publisher version: | https://doi.org/10.1093/mnras/stu2574 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Galaxy: abundances, Galaxy: halo, Galaxy: kinematics and dynamics |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10076677 |
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