122 research outputs found
Kiauhoku Stellar Evolutionary Model Grids
No full textStellar evolutionary model grids for use with Python Kiauhoku package (presented by Claytor et al. 2020). This dataset contains models from MIST, YREC, GARSTEC, and Dartmouth projects.
Model Grids
fastlaunch
Originally presented by Claytor et al. (2020). Computed using the Yale Rotating stellar Evolution Code (YREC, Pinsonneault et al. 1989) with rotational evolution computed separately using the magnetic braking law of van Saders and Pinsonneault (2013) under "fast launch" condition of Pinit ~ 8 days.
slowlaunch
Originally presented by Claytor et al. (2020). Computed using the Yale Rotating stellar Evolution Code (YREC, Pinsonneault et al. 1989) with rotational evolution computed separately using the magnetic braking law of van Saders and Pinsonneault (2013) under "slow launch" condition of Pinit ~ 13 days.
rocrit
Originally presented by Claytor et al. (2020). Computed using the Yale Rotating stellar Evolution Code (YREC, Pinsonneault et al. 1989) with rotational evolution computed separately using the stalled magnetic braking law of van Saders et al. (2016) under "fast launch" condition of Pinit ~ 8 days.
mist
Evolutionary tracks from the MESA Isochrones and Stellar Tracks (MIST, Choi et al. 2016). Computed using Modules for Experiments in Stellar Astrophysics (MESA, Paxton et al. 2010).
yrec
Originally presented by Tayar et al. (2022). Computed using the Yale Rotating stellar Evolution Code (YREC, Pinsonneault et al. 1989).
dartmouth
Originally presented by Dotter et al. (2008). Models from the Dartmouth Stellar Evolution Program (DSEP).
garstec
Originally presented by Serenelli et al. (2013). Computed using the Garching Stellar Evolution Code (GARSTEC, Weiss & Schlattl 2008).v. 2.0.1 updated Dartmouth and Garstec EEP grids to extend to RGBTip.
v. 2.0 updated directory structure for compatibility with kiauhoku v. 2.0.
v. 1.3 src and eep files provided for individual model grids.
v. 1.2 bug fixed in Dartmouth (DSEP) grid that affected placement of Terminal Age Main-Sequence EEP in ~25% of tracks.
v. 1.1 grids are identical, but added separately downloadable interpolators and grids, as well as an option for bulk download
Kiauhoku Stellar Evolutionary Model Grids
No full text<h2><strong>Deprecated, please use v. 2.0.3!</strong></h2>
<p>Stellar evolutionary model grids for use with Python Kiauhoku package (presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. 2020</a>). This dataset contains models from MIST, YREC, GARSTEC, and Dartmouth projects.</p>
<p><strong>Model Grids</strong></p>
<p><em>fastlaunch</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2013ApJ...776...67V/abstract">van Saders and Pinsonneault (2013)</a> under "fast launch" condition of <em>P</em><sub>init </sub>~ 8 days.</p>
<p><em>slowlaunch</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2013ApJ...776...67V/abstract">van Saders and Pinsonneault (2013)</a> under "slow launch" condition of <em>P</em><sub>init </sub>~ 13 days.</p>
<p><em>rocrit</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the stalled magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2016Natur.529..181V/abstract">van Saders et al. (2016)</a> under "fast launch" condition of <em>P</em><sub>init </sub>~ 8 days.</p>
<p><em>mist</em></p>
<p>Evolutionary tracks from the MESA Isochrones and Stellar Tracks (MIST, <a href="https://ui.adsabs.harvard.edu/abs/2016ApJ...823..102C/abstract">Choi et al. 2016</a>). Computed using Modules for Experiments in Stellar Astrophysics (MESA, <a href="https://ui.adsabs.harvard.edu/abs/2010ascl.soft10083P/abstract">Paxton et al. 2010</a>).</p>
<p><em>yrec</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020arXiv201207957T/abstract">Tayar et al. (2022)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>).</p>
<p><em>dartmouth</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2008ApJS..178...89D/abstract">Dotter et al. (2008)</a>. Models from the Dartmouth Stellar Evolution Program (DSEP).</p>
<p><em>garstec</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2013MNRAS.429.3645S/abstract">Serenelli et al. (2013)</a>. Computed using the Garching Stellar Evolution Code (GARSTEC, <a href="https://ui.adsabs.harvard.edu/abs/2008Ap%26SS.316...99W/abstract">Weiss & Schlattl 2008</a>).</p><p>v. 2.0.2 [Deprecated, please use v. 2.0.3!]</p>
<p>v. 2.0.1 updated Dartmouth and Garstec EEP grids to extend to RGBTip.</p>
<p>v. 2.0 updated directory structure for compatibility with kiauhoku v. 2.0.</p>
<p>v. 1.3 src and eep files provided for individual model grids.</p>
<p>v. 1.2 bug fixed in Dartmouth (DSEP) grid that affected placement of Terminal Age Main-Sequence EEP in ~25% of tracks.</p>
<p>v. 1.1 grids are identical, but added separately downloadable interpolators and grids, as well as an option for bulk download.</p>
Identifying Uncertainties in Stellar Evolution Models Using the Open Cluster M67
No full textStellar age estimates are often calculated by interpolating a star\u27s properties in a grid of models. However, different model grids will give different ages for the same star. We used the open cluster M67 to compare four different model grids: DSEP, GARSTEC, MIST, and YREC. Across all model grids, age estimates for main sequence stars were consistently higher than the accepted age of M67, while age estimates for red giant stars were lower. We compared model-generated age and mass values to external constraints as an additional test of the reliability of each model grid. For stars near solar age and metallicity, we recommend using the DSEP model grid to estimate the ages of main sequence stars and the GARSTEC model grid for red giant stars
Star-crossed Clusters: Asteroseismic Ages for Individual Stars Are in Tension with the Ages of Their Host Clusters
No full textA 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 a possible discrepancy with independent, isochrone-based age determinations for the clusters in which these stars reside. The scatter among asteroseismic ages for individual stars in any one of these clusters far surpasses both the absolute age uncertainty computed for reference cluster M92 (5.4%) and the model-to-model systematic uncertainties in isochrones (roughly 10%). This suggests that either binary processes are significantly altering the masses of stars in these clusters, or some additional corrections, perhaps as a function of mass, metallicity, or surface gravity, are required to bring the asteroseismic age scale into concordance with ages inferred from isochrone or similar model fitting
Kiauhoku Stellar Evolutionary Model Grids
No full text<p>Stellar evolutionary model grids for use with Python Kiauhoku package (presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. 2020</a>). This dataset contains models from MIST, YREC, GARSTEC, and Dartmouth projects.</p>
<p><strong>Model Grids</strong></p>
<p><em>fastlaunch</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2013ApJ...776...67V/abstract">van Saders and Pinsonneault (2013)</a> under "fast launch" condition of <em>P</em><sub>init </sub>~ 8 days.</p>
<p><em>slowlaunch</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2013ApJ...776...67V/abstract">van Saders and Pinsonneault (2013)</a> under "slow launch" condition of <em>P</em><sub>init </sub>~ 13 days.</p>
<p><em>rocrit</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the stalled magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2016Natur.529..181V/abstract">van Saders et al. (2016)</a> under "fast launch" condition of <em>P</em><sub>init </sub>~ 8 days.</p>
<p><em>mist</em></p>
<p>Evolutionary tracks from the MESA Isochrones and Stellar Tracks (MIST, <a href="https://ui.adsabs.harvard.edu/abs/2016ApJ...823..102C/abstract">Choi et al. 2016</a>). Computed using Modules for Experiments in Stellar Astrophysics (MESA, <a href="https://ui.adsabs.harvard.edu/abs/2010ascl.soft10083P/abstract">Paxton et al. 2010</a>).</p>
<p><em>yrec</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020arXiv201207957T/abstract">Tayar et al. (2022)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>).</p>
<p><em>dartmouth</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2008ApJS..178...89D/abstract">Dotter et al. (2008)</a>. Models from the Dartmouth Stellar Evolution Program (DSEP).</p>
<p><em>garstec</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2013MNRAS.429.3645S/abstract">Serenelli et al. (2013)</a>. Computed using the Garching Stellar Evolution Code (GARSTEC, <a href="https://ui.adsabs.harvard.edu/abs/2008Ap%26SS.316...99W/abstract">Weiss & Schlattl 2008</a>).</p><p>v. 2.1.0 added the full available MIST EEP tracks, rather than just a subset. </p>
<p>v. 2.0.3 fixed a minor bug in the YREC EEP tracks for M/Msun >= 1.8 that mistook the TRGB as the RGB bump. Removed the bump as an EEP; now all tracks (save one, M/Msun = 0.7, [Z/X] = +0.5) correctly reach the TRGB. fixed critical bug from v. 2.0.2.</p>
<p>v. 2.0.2 [DEPRECATED: critical bug in the yrec_eep.tar.gz file, where kiauhoku would download it, not realize it downloaded, and infinitely try to download again. This bug is only present in v 2.0.2]</p>
<p>v. 2.0.1 updated Dartmouth and Garstec EEP grids to extend to RGBTip.</p>
<p>v. 2.0 updated directory structure for compatibility with kiauhoku v. 2.0.</p>
<p>v. 1.3 src and eep files provided for individual model grids.</p>
<p>v. 1.2 bug fixed in Dartmouth (DSEP) grid that affected placement of Terminal Age Main-Sequence EEP in ~25% of tracks.</p>
<p>v. 1.1 grids are identical, but added separately downloadable interpolators and grids, as well as an option for bulk download.</p>
Kiauhoku Stellar Evolutionary Model Grids
No full text<p>Stellar evolutionary model grids for use with Python Kiauhoku package (presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. 2020</a>). This dataset contains models from MIST, YREC, GARSTEC, and Dartmouth projects.</p>
<p><strong>Model Grids</strong></p>
<p><em>fastlaunch</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2013ApJ...776...67V/abstract">van Saders and Pinsonneault (2013)</a> under "fast launch" condition of <em>P</em><sub>init </sub>~ 8 days.</p>
<p><em>slowlaunch</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2013ApJ...776...67V/abstract">van Saders and Pinsonneault (2013)</a> under "slow launch" condition of <em>P</em><sub>init </sub>~ 13 days.</p>
<p><em>rocrit</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020ApJ...888...43C/abstract">Claytor et al. (2020)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>) with rotational evolution computed separately using the stalled magnetic braking law of <a href="https://ui.adsabs.harvard.edu/abs/2016Natur.529..181V/abstract">van Saders et al. (2016)</a> under "fast launch" condition of <em>P</em><sub>init </sub>~ 8 days.</p>
<p><em>mist</em></p>
<p>Evolutionary tracks from the MESA Isochrones and Stellar Tracks (MIST, <a href="https://ui.adsabs.harvard.edu/abs/2016ApJ...823..102C/abstract">Choi et al. 2016</a>). Computed using Modules for Experiments in Stellar Astrophysics (MESA, <a href="https://ui.adsabs.harvard.edu/abs/2010ascl.soft10083P/abstract">Paxton et al. 2010</a>).</p>
<p><em>yrec</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2020arXiv201207957T/abstract">Tayar et al. (2022)</a>. Computed using the Yale Rotating stellar Evolution Code (YREC, <a href="https://ui.adsabs.harvard.edu/abs/1989ApJ...338..424P/abstract">Pinsonneault et al. 1989</a>).</p>
<p><em>dartmouth</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2008ApJS..178...89D/abstract">Dotter et al. (2008)</a>. Models from the Dartmouth Stellar Evolution Program (DSEP).</p>
<p><em>garstec</em></p>
<p>Originally presented by <a href="https://ui.adsabs.harvard.edu/abs/2013MNRAS.429.3645S/abstract">Serenelli et al. (2013)</a>. Computed using the Garching Stellar Evolution Code (GARSTEC, <a href="https://ui.adsabs.harvard.edu/abs/2008Ap%26SS.316...99W/abstract">Weiss & Schlattl 2008</a>).</p><p>v. 2.0.3 fixed a minor bug in the YREC EEP tracks for M/Msun >= 1.8 that mistook the TRGB as the RGB bump. Removed the bump as an EEP; now all tracks (save one, M/Msun = 0.7, [Z/X] = +0.5) correctly reach the TRGB. fixed critical bug from v. 2.0.2.</p>
<p>v. 2.0.2 [DEPRECATED: critical bug in the yrec_eep.tar.gz file, where kiauhoku would download it, not realize it downloaded, and infinitely try to download again. This bug is only present in v 2.0.2] </p>
<p>v. 2.0.1 updated Dartmouth and Garstec EEP grids to extend to RGBTip.</p>
<p>v. 2.0 updated directory structure for compatibility with kiauhoku v. 2.0.</p>
<p>v. 1.3 src and eep files provided for individual model grids.</p>
<p>v. 1.2 bug fixed in Dartmouth (DSEP) grid that affected placement of Terminal Age Main-Sequence EEP in ~25% of tracks.</p>
<p>v. 1.1 grids are identical, but added separately downloadable interpolators and grids, as well as an option for bulk download.</p>
A Review of the Mixing Length Theory of Convection in 1D Stellar Modeling
No full textWe review the application of the one-dimensional Mixing Length Theory (MLT) model of convection in stellar interiors and low-mass stellar evolution. We summarize the history of MLT, present a derivation of MLT in the context of 1D stellar structure equations, and discuss the physical regimes in which MLT is relevant. We review attempts to improve and extend the formalism, including to higher dimensions. We discuss the interactions of MLT with other modeling physics, and demonstrate the impact of introducing variations in the convective mixing length, αMLT, on stellar tracks and isochrones. We summarize the process of performing a solar calibration of αMLT and state-of-the-art on calibrations to non-solar targets. We discuss the scientific implications of changing the mixing length, using recent analyses for demonstration. We review the most prominent successes of MLT, and the remaining challenges, and we conclude by speculating on the future of this treatment of convection
EU-Latin America: Towards a constructive model of partnership
No full textThe article deals with the future-oriented forms in the bi-regional partnership between the European Union and Latin America and the Caribbean (LAC). The author analyses changes in the cooperation on both sides of the Atlantic Ocean with special attention to the geo-economic and geo-strategic interests of the parties due to the signing of the EU-Mercosur Trade Agreement. The author holds that the EU currently needs a renewed approach to its dialogue with the LAC. In this regard a promising form of cooperation is the joint implementation of the Sustainable Development Goals (agenda 2030). The author argues that the official development assistance and environmental programmes might be an important component of a constructive EU-LAC partnership. The EU currently implements a wide range of initiatives in sustainable development. Thus, the members of European Union seek to move forward to a new pattern of reproduction in the world economic system, based on the SDG agenda, both within the EU and in the interregional North-South cooperation. In this context, the significance of the EU and the LAC interaction in three dimensions of sustainable development - economic, social and ecological - is growing
TESS Subgiant and Lower-red-giant Asteroseismology in the Continuous Viewing Zones
No full textAsteroseismology, the study of stellar oscillations, and stellar modeling both offer profound insights into the fundamental properties and evolution of stars. With pySYD , a new open-source Python package, we were able to constrain the asteroseismic global parameters, ν _max and Δ ν , for 82 solar-like oscillating subgiant and lower red giant stars, filling in the region between the Kepler dwarfs and giants. Using asteroseismic scaling relations, we were able to compute seismic masses, radii, and surface gravities for our entire sample with average errors of 0.21 M _⊙ , 0.27 R _⊙ , and 0.06 dex, respectively. Using four stellar-modeling grids we determine and compare stellar ages for our sample. We find that our age distribution from stellar modeling is consistent with other local star samples. We find small consistent offsets from model predictions across our regime, but offsets were worse at higher gravities (log( g ) ≥ 3.5 dex), suggesting the need for better calibration. Finally, we discuss our sample in the context of galactic archaeology and show how ages like these could be used to identify and study binary system evolution and galactic evolution in the future. All in all, we show that asteroseismology can be successfully performed with TESS data and can continue to make an impact on our understanding of stellar physics and galactic archaeology
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