Navegação Ciências Exatas e da Terra por Assunto "Composicao estelar"
Resultados 1-20 de 44
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18 Sco : a solar twin rich in refractory and neutron-capture elements, implications for chemical tagging
(2014) [Artigo de periódico]We study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high-resolution (R ∼ 110,000), ... -
An empirical test of the theory of crystallization in stellar interiors
(1997) [Artigo de periódico]Our theoretical calculations indicate that the massive pulsating DA white dwarf, BPM 37093, has a crystallized ion interior. Our estimates for the crystallized mass fraction depend on our assumption for the interior ... -
An r -process enhanced star in the dwarf galaxy Tucana III
(2017) [Artigo de periódico]Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly ... -
APOGEE discovery of a chemically atypical star disrupted from NGC 6723 and captured by the Milky Way bulge
(2021) [Artigo de periódico]The central (‘bulge’) region of the Milky Way is teeming with a significant fraction of mildly metal-deficient stars with atmospheres that are strongly enriched in cyanogen (12C 14N). Some of these objects, which are also ... -
Atypical Mg-poor Milky Way field stars with globular cluster second-generation-like chemical patterns
(2017) [Artigo de periódico]We report the peculiar chemical abundance patterns of 11 atypical Milky Way (MW) field red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). These atypical giants exhibit strong ... -
Capture of field stars by globular clusters in dense bulge regions
(1997) [Artigo de periódico]The recent detection of a double red giant branch (RGB) in the optical color-magnitude diagram of the bulge globular cluster HP 1—a more populated, metal-poor, steep giant branch corresponding to the cluster itself and ... -
Cartography of Triangulum-Andromeda using SDSS stars
(2018) [Artigo de periódico]The outer Galactic halo is home to a number of substructures which still have an uncertain origin, but most likely are remnants of former interactions between the Galaxy and its former satellites. Triangulum-Andromeda ... -
Chemical abundance analysis of three α-poor, metal-poor stars in the ultrafaint dwarf galaxy Horologium I
(2018) [Artigo de periódico]We present chemical abundance measurements of three stars in the ultrafaint dwarf galaxy Horologium I, a Milky Way satellite discovered by the Dark Energy Survey. Using high-resolution spectroscopic observations, we measure ... -
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 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 ... -
Comparison of statistical treatments for the equation of state for core-collapse supernovae
(2009) [Artigo de periódico]Neutrinos emitted during the collapse, bounce, and subsequent explosion provide information about supernova dynamics. The neutrino spectra are determined by weak interactions with nuclei and nucleons in the inner regions ... -
Farthest neighbor : the distant Milky Way satellite Eridanus II
(2017) [Artigo de periódico]We present Magellan/IMACS spectroscopy of the recently discovered Milky Way satellite EridanusII (Eri II). We identify 28 member stars in EriII, from which we measure a systemic radial velocity of vhel = 75.6 1.3 (stat.) ... -
A fossil bulge globular cluster revealed by very large telescope multi-conjugate adaptive optics
(2011) [Artigo de periódico]The globular cluster HP 1 is projected on the bulge, very close to the Galactic center. The Multi-Conjugate Adaptive Optics Demonstrator on the Very Large Telescope allowed us to acquire high-resolution deep images that, ... -
Fundamental parameters of the LMC clusters NGC 1836, NGC 1860, NGC 1865, SL 444, LW 224 and SL 548
(2003) [Artigo de periódico]Complementing our recent Washington photometric studies on intermediate age and young Large Magellanic Cloud (LMC) clusters, we now turn our attention to six previously unstudied star clusters in the transition range 200–700 ... -
Fundamental parameters of the moderately young open clusters NGC 5999, NGC 6031, Ruprecht 115 and Ruprecht 120
(1999) [Artigo de periódico]We present CCD BVI Johnson–Cousins photometry for the southern open clusters NGC 5999, NGC 6031, Ruprecht 115 and Ruprecht 120. The sample consists of about 1160 stars reaching down to V ~ 19 mag. From the analysis of the ... -
GRACES observations of young [α/Fe]-rich stars
(2016) [Artigo de periódico]We measure chemical abundance ratios and radial velocities in four massive (i.e. young) [α/Fe]-rich red giant stars using high-resolution high-S/N spectra from ESPaDOnS fed by Gemini-GRACES. Our differential analysis ensures ... -
High-resolution abundance analysis of red giants in the globular cluster NGC 6522
(2014) [Artigo de periódico]Context. The [Sr/Ba] and [Y/Ba] scatter observed in some galactic halo stars that are very metal-poor and in a few individual stars of the oldest known Milky Way globular cluster NGC 6522 have been interpreted as evidence ... -
Lyman α wing absorption in cool white dwarf stars
(2011) [Artigo de periódico]Kowalski & Saumon identified the missing absorption mechanism in the observed spectra of cool white dwarf stars as the Lyman α red wing formed by the collisions between atomic and molecular hydrogen and successfully explained ... -
Matching stellar population models to bulge globular clusters
(1997) [Artigo de periódico]We compare observed color-magnitude diagrams (CMDs) of the three metal-rich bulge globular clusters NGC 6553, NGC 6528, and Terzan 5, and integrated spectral energy distributions (SEDs) of NGC 6528, and 47 Tuc, to theoretical ... -
Membership of 23 stars towards the bulge globular clusters NGC 6528 and NGC 6553
(2001) [Artigo de periódico]Low resolution spectra of 23 stars towards the bulge globular clusters NGC 6528 and NGC 6553 are analysed. Radial velocities and atmospheric parameters are derived in order to check their membership in the clusters. Effective ...
