Related papers: An ancient system hidden in the Galactic plane?
The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H]<~ -3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes of luminous stars which can be studied at high…
We test the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the our Galaxy have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] vs. [Fe/H] patterns with the ones observed in…
High resolution UVES spectra of 40 main-sequence stars with -3.3 < [Fe/H] < -1.0 are used to derive S, Fe and Zn abundances from lines in the 400 - 950 nm region. For one star we also present novel observations of the SI triplet at 1.046…
We present a comprehensive spectroscopic and kinematic analysis of the very metal-poor ([Fe/H] = -2.60 $\pm$ 0.20 dex) giant star HE2159-0551. By investigating the star's chemodynamic characteristics, we seek to address its formation,…
ABRIDGED: METHODS: We have conducted a high-resolution spectroscopic study of 714 F and G dwarf and subgiant stars in the Solar neighbourhood. The star sample has been kinematically selected to trace the Galactic thin and thick disks to…
The inner Galaxy is the most complex region of the Milky Way, comprising the bulge, inner thin and thick discs, and inner halo; the formation of the bar transferred gas and stars from the disc inward. Accretion of dwarf galaxies also…
We present the results of a detailed abundance analysis of one of the confirmed building blocks of the Milky Way stellar halo, a kinematically-coherent metal-poor stellar stream. We have obtained high resolution and high S/N spectra of 12…
We present the high resolution spectroscopic study of five -3.9<=[Fe/H]<=-2.5 stars in the Local Group dwarf spheroidal, Sculptor, thereby doubling the number of stars with comparable observations in this metallicity range. We carry out a…
Detailed chemical composition of stars is of prime interest for a range of topics in modern stellar astrophysics, such as the chemical evolution of the Galaxy or the formation, composition, and structure of exoplanets. In this work, we…
We present deep Keck spectroscopy for a sample of I<22.5 field early-type galaxies selected morphologically in the redshift range 0.56<z<1.02 in the HDF-N. Using velocity dispersions determined from the Keck spectra in conjunction with…
This paper explores the mapping between the observable properties of a stellar halo in phase- and abundance-space and the parent galaxy's accretion history in terms of the characteristic epoch of accretion and mass and orbits of progenitor…
Using $\textit{Gaia}$ DR3 astrometry and spectroscopy, we study two new substructures in the orbit-metallicity space of the inner Milky Way: $\textit{Shakti}$ and $\textit{Shiva}$. They were identified as two confined, high-contrast…
We have acquired intermediate resolution spectra in the 3700-7000 A wavelength range for a sample of 65 early-type galaxies predominantly located in low density environments, a large fraction of which show emission lines. The spectral…
We present an abundance analysis based on high resolution spectra of 10 stars selected to span the full range in metallicity in the Ursa Minor dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.35 to -3.10 dex and…
We investigate the star formation and chemical evolution in the early universe by considering the merging history of the Galaxy in the {\Lambda}CDM scenario according to the extended Press-Schechter theory. We give some possible constraints…
Large numbers of low-to-medium resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of…
We have compiled a sample of globular clusters with high quality stellar abundances from the literature to compare to the chemistries of stars in the Galaxy and those in dwarf spheroidal galaxies. Of the 45 globular clusters examined, 29…
Planets and their host stars form from the same cloud of gas and dust, so we assume that their chemical compositions are linked. However, a clear correlation between rocky planet interior properties and host star chemistry remains elusive…
Stars with higher aluminum and nitrogen enrichment are often the key pieces for the chemical makeup of multiple populations in almost all globular clusters (GCs). There is also compelling observational evidence that some Galactic components…
We present a kinematic analysis of a sample of 23,908 G- and K-type dwarfs in the Galactic disk. Based on the $\alpha$-abundance ratio, [$\alpha$/Fe], we separated our sample into low-$\alpha$ thin-disk and high-$\alpha$ thick-disk stars.…