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We report chemical abundances of 14 young $\alpha$-rich stars including neutron-capture elements based on high-quality optical spectra from HIRES/Keck I and differential line-by-line analysis. From the comparison of the abundance patterns…

太阳与恒星天体物理 · 物理学 2018-06-27 Tadafumi Matsuno , David Yong , Wako Aoki , Miho N. Ishigaki

We map the trends of elemental abundance ratios across the Galactic disk, spanning R = 3-15 kpc and midplane distance |Z|= 0-2 kpc, for 15 elements in a sample of 20,485 stars measured by the SDSS/APOGEE survey (O, Na, Mg, Al, Si, P, S, K,…

We provide the whole set of Lick indices from CN1 to TiO2 of Simple Stellar Population models with, for the first time, variable element abundance ratios, [alpha/Fe]=0.0, 0.3, 0.5, [alpha/Ca]=-0.1, 0.0, 0.2, 0.5, and [alpha/N]=-0.5, 0.0.…

天体物理学 · 物理学 2009-11-07 Daniel Thomas , Claudia Maraston , Ralf Bender

HARPS-N spectra with S/N > 250 and MARCS model atmospheres were used to derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B) selected…

太阳与恒星天体物理 · 物理学 2017-12-13 P. E. Nissen , V. Silva Aguirre , J. Christensen-Dalsgaard , R. Collet , F. Grundahl , D. Slumstrup

A sample of warm low level semi-regular variables chosen from the General Catalogue of Variable Stars is studied for their chemical compositions by analysing high resolution optical spectra. The abundance ratios from Na/Fe to Eu/Fe…

星系天体物理 · 物理学 2024-06-18 Ramya Pozhath , David L. Lambert

We have previously reported on chemical abundance trends with evolutionary state in the globular cluster NGC 6397 discovered in analyses of spectra taken with FLAMES at the VLT. Here, we reinvestigate the FLAMES-UVES sample of 18 stars,…

太阳与恒星天体物理 · 物理学 2012-09-24 T. Nordlander , A. J. Korn , O. Richard , K. Lind

We use our new, flux-calibrated stellar population model of absorption-line indices to derive ages, metallicities, and various element abundance ratios from integrated light spectroscopy of galactic globular clusters. The ages agree well…

宇宙学与河外天体物理 · 物理学 2015-05-20 Daniel Thomas , Jonas Johansson , Claudia Maraston

Context: A small number of K-type giants on the red giant branch (RGB) is known to be very rich in lithium (Li). This fact is not accounted for by standard stellar evolution theory. The exact phase and mechanism of Li enrichment is still a…

太阳与恒星天体物理 · 物理学 2015-06-03 Thomas Lebzelter , Stefan Uttenthaler , Maurizio Busso , Mathias Schultheis , Bernhard Aringer

The Galactic Centre (GC) has experienced a high degree of recent star-forming activity, as evidenced by the large number of massive stars currently residing there. The relative abundances of chemical elements in the GC may provide insights…

The atmospheric parameters and abundances of Mg, Si, Ca, and Ti have been determined for 20 stars using the Gaia DR2 parallaxes, high-resolution spectra, and the non-local thermodynamic equilibrium (non-LTE) line formation modeling. A…

太阳与恒星天体物理 · 物理学 2019-09-04 Lyudmila Mashonkina , Maria Neretina , Tatyana Sitnova , Yuri Pakhomov

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…

太阳与恒星天体物理 · 物理学 2025-02-27 Sanil Mittal , Ian U. Roederer

We report on detailed abundances of giants in the Galactic bulge, measured with the HIRES echelle spectrograph on the 10-m Keck telescope. We also review other work on the bulge field population and globular clusters using Keck/HIRES. Our…

天体物理学 · 物理学 2015-06-24 R. M. Rich , A. McWilliam

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…

天体物理学 · 物理学 2008-08-09 Evan N. Kirby , Puragra Guhathakurta , Christopher Sneden

We discuss oxygen and iron abundance patterns in K and M red-giant members of the Galactic bulge and in the young and massive M-type stars inhabiting the very center of the Milky Way. The abundance results from the different bulge studies…

天体物理学 · 物理学 2009-11-13 K. Cunha , V. Smith , K. Sellgren , R. Blum , S. Ramirez , D. Terndrup

We used the spectroscopic and astrometric data provided from the GALAH DR2 and Gaia DR2, respectively, for a large sample of stars to investigate the behaviour of the [$\alpha$/Fe] abundances via two procedures, i.e. kinematically and…

星系天体物理 · 物理学 2019-11-13 S. Karaali , S. Bilir , E. Yaz Gokce , O. Plevne

Context: Accurate fundamental parameters of stars are essential for the asteroseismic analysis of data from the NASA Kepler mission. Aims: We aim at determining accurate atmospheric parameters and the abundance pattern for a sample of 82…

We present chemical elemental abundances for $36,561$ stars observed by the RAdial Velocity Experiment (RAVE), an ambitious spectroscopic survey of our Galaxy at Galactic latitudes $|$b$|>25^{\circ}$ and with magnitudes in the range…

We present detailed chemical abundances in 8 clusters in the Large Magellanic Cloud (LMC). We measure abundances of 22 elements for clusters spanning a range in age of 0.05 to 12 Gyr, providing a comprehensive picture of the chemical…

星系天体物理 · 物理学 2015-06-03 J. E. Colucci , R. A. Bernstein , S. A. Cameron , A. McWilliam

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…

星系天体物理 · 物理学 2016-03-09 P. François , L. Monaco , P. Bonifacio , C. Moni Bidin , D. Geisler , L. Sbordone

We analyze a high-resolution spectrum of a microlensed G-dwarf in the Galactic bulge, acquired when the star was magnified by a factor of 110. We measure a spectroscopic temperature, derived from the wings of the Balmer lines, that is the…

天体物理学 · 物理学 2009-11-13 Jennifer A. Johnson , B. Scott Gaudi , Takahiro Sumi , Ian A. Bond , Andrew Gould