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A number of large spectroscopic surveys of stars in the Milky Way are under way or are being planned. In this context it is important to discuss the extent to which elemental abundances can be used as discriminators between different (known…

Astrophysics of Galaxies · Physics 2015-06-15 Lennart Lindegren , Sofia Feltzing

Using 8.4 years of photometry from the AllWISE/NEOWISE multi-epoch catalogs, we compare the mid-infrared variability properties of a sample of 2197 dwarf galaxies (M_stellar < 2 x 10^9 h^-2 M_sun) to a sample of 6591 more massive galaxies…

Astrophysics of Galaxies · Physics 2020-09-09 Nathan Secrest , Shobita Satyapal

Large stellar surveys are revealing the chemodynamical structure of the Galaxy across a vast spatial extent. However, the many millions of low-resolution spectra observed to date are yet to be fully exploited. We employ The Cannon, a…

We explore the elemental abundances in Galactic planetary nebulae (PNe) compared with those of their stellar progenitors (Red Giant Branch and Asymptotic Giant Branch, RGB and AGB, stars), to explore and quantify the expected -- i.e., due…

Astrophysics of Galaxies · Physics 2024-07-09 Letizia Stanghellini , Verne V. Smith , Katia Cunha , Nikos Prantzos

We have performed a detailed abundance analysis of 10 red giant members of the heavily obscured bulge globular cluster HP~1 using high-resolution, high S/N near-infrared spectra collected with the Apache Point Observatory Galactic Evolution…

Astrophysics of Galaxies · Physics 2025-04-16 Lady Henao , Sandro Villanova , Doug Geisler , José G. Fernández-Trincado

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) provides spectroscopic information of regions of the inner Milky Way inaccessible to optical surveys. We present the first large study of the metallicity distribution of…

We report for the first time on the magnitude of the intrinsic [Fe/H] spread among ten old globular clusters (GCs) of the Large Magellanic Cloud (LMC). Such spreads are merely observed in approximately five per cent of the Milky Way GCs and…

Astrophysics of Galaxies · Physics 2018-10-31 Andrés E. Piatti , Andreas Koch

Understanding the assembly of our Galaxy requires us to also characterize the systems that helped build it. In this work, we accomplish this by exploring the chemistry of accreted halo stars from the Gaia-Enceladus/Gaia-Sausage (GES)…

Solar and Stellar Astrophysics · Physics 2022-05-04 Andreia Carrillo , Keith Hawkins , Paula Jofré , Danielle de Brito Silva , Payel Das , Madeline Lucey

To understand the formation and evolution of the Milky Way disk, we must connect its current properties to its past. We explore hydrodynamical cosmological simulations to investigate how the chemical abundances of stars might be linked to…

The Keck I telescope has been used to obtain HIRES spectra for red giants belonging to the Draco, Sextans and Ursa Minor dwarf spheroidal (dSph) galaxies. An analysis of these spectra is presented, along with abundance ratios for more than…

Astrophysics · Physics 2011-08-23 Matthew Shetrone , Patrick Cote , W. L. W. Sargent

We use broadband photometry and low-resolution spectra of a complete sample of late-K and M dwarfs brighter than I=22 in three fields at high galactic latitude to study issues relating to galactic structure and large scale abundance…

Astrophysics · Physics 2009-10-30 I. N. Reid , J. E. Gizis , J. G. Cohen , M. A. Pahre , D. W. Hogg , L. Cowie , E. Hu , A. Songaila

We present a technique that applies spectral synthesis to medium resolution spectroscopy (MRS, R ~ 6000) in the red (6300 A < lambda < 9100 A) to measure [Fe/H] and [alpha/Fe] of individual red giant stars over a wide metallicity range. We…

Astrophysics · Physics 2008-08-09 Evan N. Kirby , Puragra Guhathakurta , Christopher Sneden

Based on a simple, but fairly successful, model of the chemical evolution of the Milky Way disk, we study the evolution of the abundances of the elements He, C, N, O, Ne, Mg, Al, Si, S, Ar and Fe. We use metallicity dependent yields for…

Astrophysics · Physics 2007-05-23 J. L. Hou , N. Prantzos , S. Boissier

Metallicity gradients provide strong constraints for understanding the chemical evolution of the Galaxy. We report on radial abundance gradients of Fe, Ni, Ca, Si, and Mg obtained from a sample of 304 red-giant members of 29 disk open…

We have derived Mn abundances for more than 200 stars in 19 globular clusters. In addition, Mn abundance determinations have been made for a comparable number of halo field and disk stars possessing an overlapping range of metallicities and…

This paper is the fourth in a series whose purpose is to study the interstellar abundances of sulfur, chlorine, and argon in the Galaxy using a sample of 86 planetary nebulae. Here we present new high-quality spectrophotometric observations…

Astrophysics · Physics 2009-11-07 K. B. Kwitter , R. B. C. Henry , J. B. Milingo

(ABRIDGED) Globular clusters trace the formation and evolution of the Milky Way and surrounding galaxies, and outline their chemical enrichment history. To accomplish these tasks it is important to have large samples of clusters with…

Astrophysics of Galaxies · Physics 2016-05-04 Bruno Dias , Beatriz Barbuy , Ivo Saviane , Enrico Held , Gary Da Costa , Sergio Ortolani , Marco Gullieuszik , Sergio Vasquez

We examine the distribution of the [O/Fe] abundance ratio in stars across the Galactic disk using H-band spectra from the Apache Point Galactic Evolution Experiment (APOGEE). We minimize systematic errors by considering groups of stars with…

We present equivalent widths, improved model atmosphere parameters, and revised abundances for 14 species of 11 elements derived from high resolution optical spectroscopy of 311 metal-poor stars. All of these stars had their parameters…

Solar and Stellar Astrophysics · Physics 2025-02-27 Sanil Mittal , Ian U. Roederer

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…