Related papers: An ancient system hidden in the Galactic plane?
Ancient, very metal-poor stars offer a window into the earliest epochs of galaxy formation and assembly. We combine data from the H3 Spectroscopic Survey and Gaia to measure metallicities, abundances of $\alpha$ elements, stellar ages, and…
The origin of very metal-poor (VMP; [Fe/H] $\leq -2.0$) stars on planar orbits has been the subject of great attention since their first discovery. However, prior to the release of the Gaia BP/RP (XP) spectra, and large photometric samples…
Low mass dwarf spheroidal galaxies are key objects for our understanding of the chemical evolution of the pristine Universe and the Local Group of galaxies. Abundance ratios in stars of these objects can be used to better understand their…
We explore the chemo-dynamical properties of a sample of very metal-poor (VMP) stars selected from the Hamburg/ESO survey, matched with Gaia EDR3, in the phase-space identified by the three integrals of motion ($L_z$, $E$, $I_3$). Disk and…
We present a chemical abundance distribution study in 14 $\alpha$, odd-Z, even-Z, light, and Fe-peak elements of approximately 3200 intermediate metallicity giant stars from the APOGEE survey. The main aim of our analysis is to explore the…
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 $\sim$ 3M giant stars with Gaia DR3 XP-based \textit{Pristine-Gaia}…
We use photometric metallicity estimates for about 700000 stars in the surroundings of the Sun, with very accurate distances and 3-D motions measures from Gaia DR3, to explore the properties of the metal-poor (-2.0<[Fe/H]<= -1.5; MP) and…
We performed an uniform spectroscopic analysis of 1111 FGK dwarfs observed as part of the HARPS GTO planet search program. We applied a purely chemical approach, based on [alpha/Fe] ratio, to distinguish the various stellar components in…
The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar populations, with older generation stars showing higher $\alpha$-element abundances while the later generations becoming enriched…
The early chemical evolution of the Galaxy and the Universe is vital to our understanding of a host of astrophysical phenomena. Since the most metal-poor Galactic stars (with metallicities down to [Fe/H]\sim-5.5) are relics from the…
We have compiled a sample of 699 stars from the recent literature with detailed chemical abundance information (spanning -4.2 < [Fe/H] < +0.3), and we compute their space velocities and Galactic orbital parameters. We identify members of…
In this work, we study the chemical compositions and kinematic properties of six metal-poor stars with [Fe/H] $< -2.5$ in the Galactic halo. From high-resolution (R $\sim$~110,000) spectroscopic observations obtained with the Lick/APF, we…
We have analyzed high-resolution and high signal-to-noise ratio optical spectra of nearby FGK stars with and without detected giant planets in order to homogeneously measure their photospheric parameters, mass, age, and the abundances of…
High-resolution, high-signal-to-noise (<S/N> = 85) spectra have been obtained for five stars -- CD-24:17504, CD-38:245, CS 22172-002, CS 22885-096, and CS 22949-037 -- having [Fe/H] < -3.5 according to previous lower S/N material. LTE…
Our knowledge about the chemical evolution of the more luminous dwarf spheroidal (dSph) galaxies is constantly growing. However, little is known about the enrichment of the ultrafaint systems recently discovered in large numbers in large…
We present homogeneous abundance analysis of over 20 elements for 385 very metal-poor (VMP) stars based on the LAMOST survey and follow-up observations with the Subaru Telescope. It is the largest high-resolution VMP sample (including 363…
The earliest phases of the chemical evolution of our Galaxy are analysed in the light of the recent VLT results (concerning abundance patterns in the most metal-poor stars of the Galactic halo) and of stellar nucleosynthesis calculations.…
Based on 4,\,098 very metal-poor (VMP) stars with 6D phase-space and chemical information from \textit{Gaia} DR3 and LAMOST DR9 as tracers, we apply an unsupervised machine learning algorithm, Shared Nearest Neighbor (SNN), to identify…
Metal-poor stars are key for studying the formation and evolution of the Galaxy. Evidence of the early mergers that built up the Galaxy remains in the distributions of abundances, kinematics, and orbital parameters of its stars. Several…
We explore the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1), based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution…