The Pristine survey XXIV: The Galactic underdogs -- Dynamic tales of a Milky Way metal-poor population
Isaure Gonz\'alez Rivera de La Vernhe, Vanessa Hill, Georges, Kordopatis, Felipe Gran, Emma Fern\'andez-Alvar, Anke Ardern-Arentsen,, Guillaume F. Thomas, Federico Sestito, Camila Navarrete, Nicolas F. Martin,, Else Starkenburg, Akshara Viswanathan, Giuseppina Battaglia

TL;DR
This study characterizes very metal-poor stars in the Milky Way, revealing a subset with disc-like orbits likely associated with a metal-weak thick disc, challenging previous assumptions about their origins.
Contribution
It provides a large, decontaminated sample of very metal-poor stars with detailed chemodynamical analysis, identifying a distinct prograde, planar population linked to the metal-weak thick disc.
Findings
Identified a prograde, planar subset of very metal-poor stars with disc-like kinematics.
Found evidence supporting the existence of a metal-weak thick disc component.
Ruled out thin disc association for the highly prograde, metal-poor stars.
Abstract
Through the chemodynamical characterisation of metal-poor stars, one can efficiently probe the early history of the Milky Way. We aim at decontaminating a sample of 3M giant stars with Gaia DR3 XP-based \textit{Pristine-Gaia} metallicities, to investigate a subset of very metal-poor stars ([Fe/H] < -1.7) with disc-like orbits. We construct a statistically robust sample of 36 000 very metal-poor giants, using APOGEE and LAMOST to estimate and remove contamination from high stars. We investigate the spatial and kinematic properties of the decontaminated sample, using and the action space, both powerful to disentangle stellar populations. As in previous works, we find a pronounced asymmetry in and in favour of prograde stars. This excess is mostly made of prograde-planar stars (10% of the very metal-poor population), and contains stars with…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsArchaeology and ancient environmental studies
