ترغب بنشر مسار تعليمي؟ اضغط هنا

Database of Geneva stellar evolution tracks and isochrones for UBVRIJHKLLM, HST-WFPC2, Geneva and Washington photometric systems

109   0   0.0 ( 0 )
 نشر من قبل Daniel Schaerer
 تاريخ النشر 2000
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Thibault Lejeune




اسأل ChatGPT حول البحث

We have used an updated version of the empirically and semi-empirically calibrated BaSeL library of synthetic stellar spectra of Lejeune et al. (1997, 1998) and Westera et al. (1999) to calculate synthetic photometry in the UBVRIJHKLLM, HST-WFPC2, Geneva, and Washington systems for the entire set of non-rotating Geneva stellar evolution models covering masses from 0.4-0.8 to 120-150 Msun and metallicities Z=0.0004 (1/50 Zsun) to 0.1 (5 Zsun). The results are provided in a database which includes all individual stellar tracks and the corresponding isochrones covering ages from 10^3 yr to 16--20 Gyr in time steps of Delta(log t)= 0.05 dex. The database also includes a new grid of stellar tracks of very metal-poor stars (Z=0.0004) from 0.8 - 150 Msun calculated with the Geneva stellar evolution code. The full database will be available in electronic form at the CDS (http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/(vol)/(page)) and at http://webast.ast.obs-mip.fr/stellar/.



قيم البحث

اقرأ أيضاً

We present the updated version of the code used to compute stellar evolutionary tracks in Padova. It is the result of a thorough revision of the major input physics, together with the inclusion of the pre-main sequence phase, not present in our previ ous releases of stellar models. Another innovative aspect is the possibility of promptly generating accurate opacity tables fully consistent with any selected initial chemical composition, by coupling the OPAL opacity data at high temperatures to the molecular opacities computed with our AESOPUS code (Marigo & Aringer 2009). In this work we present extended sets of stellar evolutionary models for various initial chemical compositions, while other sets with different metallicities and/or different distributions of heavy elements are being computed. For the present release of models we adopt the solar distribution of heavy elements from the recent revision by Caffau et al. (2011), corresponding to a Suns metallicity Z=0.0152. From all computed sets of stellar tracks, we also derive isochrones in several photometric systems. The aim is to provide the community with the basic tools to model star clusters and galaxies by means of population synthesis techniques.
Based on a large sample of disk and halo giant stars, for which accurate effective temperatures derived through the InfraRed Flux Method (IRFM) exist, a calibration of the temperature scale in the Vilnius, Geneva, RI(C) and DDO photometric systems is performed. We provide calibration formulae for the metallicity dependent T_eff vs color relations as well as grids of intrinsic colors and compare them with other calibrations. Photometry, atmospheric parameters and reddening corrections for the stars of the sample have been updated with respect to the original sources in order to reduce the dispersion of the fits. Application of our results to Arcturus leads to an effective temperature in excellent agreement with the value derived from its angular diameter and integrated flux. The effects of gravity on these T_eff vs color relations are also explored by taking into account our previous results for dwarf stars.
132 - S.Theado , G. Alecian , F. LeBlanc 2012
Atomic diffusion has been recognized as an important process that has to be considered in any computations of stellar models. In solar-type and cooler stars, this process is dominated by gravitational settling, which is now included in most stellar e volution codes. In hotter stars, radiative accelerations compete with gravity and become the dominant ingredient in the diffusion flux for most heavy elements. Introducing radiative accelerations into the computations of stellar models modifies the internal element distribution and may have major consequences on the stellar structure. Coupling these processes with hydrodynamical stellar motions has important consequences that need to be investigated in detail. We aim to include the computations of radiative accelerations in a stellar evolution code (here the TGEC code) using a simplified method (SVP) so that it may be coupled with sophisticated macroscopic motions. We also compare the results with those of the Montreal code in specific cases for validation and study the consequences of these coupled processes on accurate models of A- and early-type stars. We implemented radiative accelerations computations into the Toulouse-Geneva stellar evolution code following the semi-analytical prescription proposed by Alecian and LeBlanc. This allows more rapid computations than the full description used in the Montreal code. We present results for A-type stellar models computed with this updated version of TGEC and compare them with similar published models obtained with the Montreal evolution code. We discuss the consequences for the coupling with macroscopic motions, including thermohaline convection.
This is the first of a series of papers presenting the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks (MIST) project, a new comprehensive set of stellar evolutionary tracks and isochrones computed using MESA, a s tate-of-the-art open-source 1D stellar evolution package. In this work, we present models with solar-scaled abundance ratios covering a wide range of ages ($5 leq rm log(Age);[yr] leq 10.3$), masses ($0.1 leq M/M_{odot} leq 300$), and metallicities ($-2.0 leq rm [Z/H] leq 0.5$). The models are self-consistently and continuously evolved from the pre-main sequence to the end of hydrogen burning, the white dwarf cooling sequence, or the end of carbon burning, depending on the initial mass. We also provide a grid of models evolved from the pre-main sequence to the end of core helium burning for $-4.0 leq rm [Z/H] < -2.0$. We showcase extensive comparisons with observational constraints as well as with some of the most widely used existing models in the literature. The evolutionary tracks and isochrones can be downloaded from the project website at http://waps.cfa.harvard.edu/MIST/.
94 - A. Pietrinferni 2004
We present a large and updated stellar evolution database for low-, intermediate- and high-mass stars in a wide metallicity range, suitable for studying Galactic and extragalactic simple and composite stellar populations using population synthesis te chniques. The stellar mass range is between sim0.5Mo and 10Mo with a fine mass spacing. The metallicity [Fe/H] comprises 10 values ranging from -2.27 to 0.40, with a scaled solar metal distribution. The initial He mass fraction ranges from Y=0.245, for the more metal-poor composition, up to 0.303 for the more metal-rich one, with Delta Y/Delta Zsim 1.4. For each adopted chemical composition, the evolutionary models have been computed without and with overshooting from the Schwarzschild boundary of the convective cores during the central H-burning phase. The whole set of evolutionary models can be used to compute isochrones in a wide age range, from sim30 Myr to sim15Gyr. Both evolutionary tracks and isochrones are available in several observational planes, employing updated set of bolometric corrections and color-Te relations computed for this project. The number of points along the models and the resulting isochrones is selected in such a way that interpolation for intermediate metallicities not contained in the grid is straightforward. We compare our isochrones with results from different stellar evolution databases and perform some empirical tests for the reliability of our models. Since this work is devoted to scaled solar compositions, we focus our attention on the Galactic disk populations, employing multicolor photometry of unevolved field MS stars with precise Hipparcos parallaxes, well-studied open clusters and one eclipsing binary system with precise measurements of masses, radii and [Fe/H] of both components.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا