Related papers: Towards precise stellar ages: combining isochrone …
High-quality Hipparcos data for a complete sample of nearly 12000 main-sequence and subgiant stars, together with Padua isochrones, are used to constrain the star-formation history of the solar neigbourhood and the processes that…
The ages of the oldest and most metal-poor stars in the Milky Way bear important information on the age of the Universe and its standard model. We analyze a sample of 28 extremely metal-poor field stars in the solar vicinity culled from the…
We present a dense grid of evolutionary tracks and isochrones of rotating massive main-sequence stars. We provide three grids with different initial compositions tailored to compare with early OB stars in the Small and Large Magellanic…
Using asteroseismic data and stellar evolution models we make the first detection of a convective core in a Kepler field main-sequence star, putting a stringent constraint on the total size of the mixed zone and showing that extra mixing…
Aims: Our aim is to obtain ages that are as accurate as possible for the seven nearby open clusters alpha Per, Coma Ber, IC 2602, NGC 2232, NGC 2451A, NGC 2516, and NGC 6475, each of which contains at least one magnetic Ap or Bp star.…
The observed mass-age-rotation relationship in open clusters shows the progressive development of a slow-rotators sequence. The observed clustering on this sequence suggests that it corresponds to some equilibrium or asymptotic condition…
In this work, we perform a full-spectrum fitting of 350 massive and passive galaxies selected as cosmic chronometers from the LEGA-C ESO public survey to derive their stellar ages, metallicities, and star-formation histories. We extensively…
The combination of spectroscopic stellar metallicities and resolved star color-magnitude diagrams (CMDs) has the potential to constrain the entire star formation and chemical enrichment history (SFH) of a galaxy better than fitting CMDs…
We present a sample of local red giant stars observed using the New Mexico State University 1 m telescope with the APOGEE spectrograph, for which we estimate stellar ages and the age distribution from the high-resolution spectroscopic…
Context: The formation and evolution of disk galaxies are long standing questions in Astronomy. Understanding the properties of globular cluster systems can lead to important insights on the evolution of its host galaxy. Aims: We aim to…
A meta-analysis of seismic ages determined for individual stars in the well-studied open and globular clusters NGC 6819, NGC 6791, M67, M4, M19, M80, and M9 reveals both high variance across measurements and significant discrepancy with…
Solar twins are stars with similar stellar (surface) parameters to the Sun that can have a wide range of ages. This provide an opportunity to analyze the variation of their chemical abundances with age. Nissen (2015) recently suggested that…
Determining reliable ages for old stellar objects at different redshifts offers a powerful means to constrain cosmology without relying on a specific cosmological model: this is known as the cosmic clocks method. Globular clusters (GCs),…
We present a maximum likelihood method for fitting two-dimensional model distributions to stellar data in colour-magnitude space. This allows one to include (for example) binary stars in an isochronal population. The method also allows one…
Methods. We used the HIRES spectrograph on the Keck I telescope to acquire high-resolution (R $\approx$ 70000) spectra with a high signal-to-noise ratio (S/N $\approx$ 400 - 650 per pixel) of HIP 100963 and the Sun for a differential…
Ages of extragalactic globular clusters can provide valuable insights into the formation and evolution of galaxies. In this contribution the photometric methods of age dating old globular cluster systems are summarised. The spectroscopic…
The accuracy of masses of pre-main sequence (PMS) stars derived from their locations on the Hertzsprung-Russell Diagram (HRD) can be tested by comparison with accurate and precise masses determined independently. We present 29 single stars…
We investigated the age-metallicity relation using a sample of 5691 F and G type dwarfs from RAVE DR3 by applying several constraints: i) We selected stars with surface gravities log g < 3.8 and effective temperatures in the…
We review the history of the discovery of field subgiant stars and their importance in the age dating of the Galactic disk. We use the cataloged data from the Hipparcos satellite in this latter capacity. Based on Hipparcos parallaxes…
We present a new technique to fit color-magnitude diagrams of open clusters based on the Cross-Entropy global optimization algorithm. The method uses theoretical isochrones available in the literature and maximizes a weighted likelihood…