Navegação Ciências Exatas e da Terra por Assunto "Galaxy: abundances"
Resultados 1-17 de 17
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Ages and metallicities of circumnuclear star formation regions from Gemini IFU observations
(2008) [Artigo de periódico]Aims. We derive the age and metallicity of circumnuclear star formation regions (CNSFRs) located in the spiral galaxies NGC6951 and NGC1097 and investigate the cause of the very low equivalent widths of emission lines found ... -
Chemical abundances in bright giants of the globular cluster M62 (NGC 6266)
(2014) [Artigo de periódico]With the exception of Terzan 5, all the Galactic globular clusters that possess significant metallicity spreads, such as ω Cen and M22, are preferentially the more luminous clusters with extended horizontal branches. Here ... -
Chemical abundances in the metal-intermediate GC NGC 6723
(2019) [Artigo de periódico]We have performed a detailed spectral analysis of the inner halo Galactic globular cluster (GC) NGC 6723 using high-resolution (R≈ 22 000–48 000) spectra for for 11 red giant branch stars collected with MIKE (Magellan) and ... -
Chemical analysis of eight giant stars of the globular cluster NGC 6366
(2018) [Artigo de periódico]The metal-rich Galactic globular cluster NGC6366 is the fifth closest to the Sun. Despite its interest, it has received scarce attention, and little is known about its internal structure. Its kinematics suggests a link to ... -
Chemodynamics of the Milky Way I. The first year of APOGEE data
(2014) [Artigo de periódico]Context. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) features the first multi-object high-resolution fiber spectrograph in the near-infrared ever built, thus making the survey unique in its capabilities: ... -
Dissecting stellar chemical abundance space with t-SNE
(2018) [Artigo de periódico]In the era of large-scale Galactic astronomy and multi-object spectroscopic stellar surveys, the sample sizes and the number of available stellar chemical abundances have reached dimensions in which it has become difficult ... -
Estimating stellar birth radii and the time evolution of Milky Way’s ISM metallicity gradient
(2018) [Artigo de periódico]We present a semi-empirical, largelymodel-independent approach for estimatingGalactic birth radii, rbirth, for Milky Way disc stars. The technique relies on the justifiable assumption that a negative radial metallicity ... -
Galactic archaeology with asteroseismology and spectroscopy : red giants observed by CoRoT and APOGEE
(2017) [Artigo de periódico]With the advent of the space missions CoRoT and Kepler, it has recently become feasible to determine precise asteroseismic masses and relative ages for large samples of red giant stars. We present the CoRoGEE dataset, ... -
Mass loss from red giant stars in M67 : is there any evidence for a metallicity dependence?
(1996) [Artigo de periódico]Recent claims in the literature, that the rate of mass loss from red giant branch (RGB) stars in old, open clusters like M 67 and NGC 6791, increases with the metallicity above the value holding for Globular Clusters and ... -
Multiband photometry towards the inner galactic bulge : extinction, atmospheric parameters, and metallicities
(2006) [Artigo de periódico]Context. We have obtained BVRI photometry for 21 stellar fields located in directions towards the central 3.5° of the Galaxy. Each field is 10 × 10 arcmin in size, and a total of ∼2 × 105 stars were measured. Aims. Previous ... -
NGC 6522 : an intermediate metallicity globular cluster projected on the baade window
(1994) [Artigo de periódico]We studied NGC 6522 colour magnitude diagrams using CCD photometry with BV filters. We have carefully estimated the reddening, which is criticai for Baade Window studies, obtaining E(B-V) = 0.55. We derive for this ... -
Red giants observed by CoRoT and APOGEE : the evolution of the Milky Way’s radial metallicity gradient
(2017) [Artigo de periódico]Using combined asteroseismic and spectroscopic observations of 418 red-giant stars close to the Galactic disc plane (6 kpc < RGal < 13 kpc, lZGall < 0.3 kpc), we measure the age dependence of the radial metallicity ... -
SDSS-IV MaNGA : properties of galaxies with kinematically decoupled stellar and gaseous components
(2016) [Artigo de periódico]We study the properties of 66 galaxies with kinematically misaligned gas and stars from MaNGA survey. The fraction of kinematically misaligned galaxies varies with galaxy physical parameters, i.e. M∗, SFR and sSFR. According ... -
Target selection for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)
(2013) [Artigo de periódico]The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution infrared spectroscopic survey spanning all Galactic environments (i.e., bulge, disk, and halo), with the principal goal of constraining ... -
The temporal evolution of neutron-capture elements in the Galactic discs
(2018) [Artigo de periódico]Important insights into the formation and evolution of the Galactic disc(s) are contained in the chemical compositions of stars.We analysed high-resolution and high signal-to-noise HARPS spectra of 79 solar twin stars in ... -
V, i photometry of the metal-rich bulge globular cluster terzan 2
(1997) [Artigo de periódico]We present for the rst time optical colour magnitude diagrams of the globular cluster Terzan 2, in the V, I colours. The horizontal branch is red. The red giant branch morphology can be fitted with that of 47 Tuc, but ... -
Young (α/Fe)-enhanced stars discovered by CoRoT and APOGEE : what is their origin?
(2015) [Artigo de periódico]We report the discovery of a group of apparently young CoRoT red-giant stars exhibiting enhanced [ /Fe] abundance ratios (as determined from APOGEE spectra) with respect to solar values. Their existence is not explained ...
