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Related papers: The Cooling of Old White Dwarfs in 47 Tucanae

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We present an empirical determination of the white dwarf cooling sequence in the globular cluster 47 Tucanae. Using spectral models, we determine temperatures for 887 objects from Wide Field Camera 3 data, as well as 292 objects from data…

Solar and Stellar Astrophysics · Physics 2015-06-11 R. Goldsbury , J. Heyl , H. B. Richer , P. Bergeron , A. Dotter , J. S. Kalirai , J. MacDonald , R. M. Rich , P. B. Stetson , P. -E. Tremblay , K. A. Woodley

47 Tucanae is one of the most interesting and well observed and theoretically studied globular clusters. This allows us to study the reliability of our understanding of white dwarf cooling sequences, to confront different methods to…

Astrophysics of Galaxies · Physics 2015-06-23 Enrique García-Berro , Santiago Torres , Leandro G. Althaus , Marcelo M. Miller Bertolami

Using images from the Hubble Space Telescope Advanced Camera for Surveys, we measure the rate of cooling of white dwarfs in the globular cluster 47 Tucanae and compare it to modelled cooling curves. We examine the effects of the outer…

Solar and Stellar Astrophysics · Physics 2017-10-26 Alysa Obertas , Ilaria Caiazzo , Jeremy Heyl , Harvey Richer , Jason Kalirai , Pier-Emmanuel Tremblay

We present a robust statistical analysis of the white dwarf cooling sequence in 47 Tucanae. We combine HST UV and optical data in the core of the cluster, Modules for Experiments in Stellar Evolution (MESA) white dwarf cooling models, white…

Solar and Stellar Astrophysics · Physics 2016-04-20 Ryan Goldsbury , Jeremy Heyl , Harvey Richer , Jason Kalirai , Pier-Emmanuel Tremblay

We present a study of the white dwarf (WD) cooling sequence of the globular cluster 47 Tucanae (47 Tuc or NGC 104) using deep infrared observations with the James Webb Space Telescope (JWST). By combining these data with ultra-deep optical…

Solar and Stellar Astrophysics · Physics 2025-06-27 M. Salaris , M. Scalco , L. R. Bedin , S. Cassisi

We present Hubble Space Telescope observations of the upper part (T_eff> 10 000 K) of the white dwarf cooling sequence in the globular cluster 47 Tucanae and measure a luminosity function of hot white dwarfs. Comparison with previous…

Solar and Stellar Astrophysics · Physics 2015-08-26 Bradley Hansen , Harvey Richer , Jason Kalirai , Ryan Goldsbury , Shane Frewen , Jeremy Heyl

We analyse the cooling of white dwarfs in the globular cluster 47 Tucanae to look for evidence of axion emission affecting the rate of white dwarf cooling. If axions exist and couple to electrons, then axions could be produced at an…

Solar and Stellar Astrophysics · Physics 2025-11-27 Leesa Fleury , Alysa Obertas , Harvey Richer , Jeremy Heyl

Cooling white dwarfs (WDs) can yield accurate ages when theoretical cooling models fully account for the physics of the dense plasma of WD interiors. We use MESA to investigate cooling models for a set of massive and ultra-massive WDs…

Solar and Stellar Astrophysics · Physics 2020-10-21 Evan B. Bauer , Josiah Schwab , Lars Bildsten , Sihao Cheng

An accurate assessment of white dwarf cooling times is paramount to place white dwarf cosmochronology of Galactic populations on more solid grounds. This issue is particularly relevant in view of the enhanced observational capabilities…

Solar and Stellar Astrophysics · Physics 2015-06-16 Maurizio Salaris , Leandro G. Althaus , Enrique García-Berro

We investigate in detail the white dwarf cooling sequence of the globular cluster Messier 4. In particular we study the influence of various systematic uncertainties, both observational and theoretical, on the determination of the cluster…

Cooling ages of white dwarfs are routinely determined by mapping effective temperatures and masses to ages using evolutionary models. Typically, the reported uncertainties on cooling ages only consider the error propagation of the…

Solar and Stellar Astrophysics · Physics 2025-03-12 Praneet Pathak , Simon Blouin , Falk Herwig

We present new cooling sequences, color-magnitude diagrams, and color-color diagrams for cool white dwarfs with pure hydrogen atmospheres down to an effective temperature $\te=1500$ K. We include a more detailed treatment of the physics of…

Astrophysics · Physics 2009-10-31 Gilles Chabrier , Pierre Brassard , Gilles Fontaine , Didier Saumon

Using images from the Hubble Space Telescope Wide-Field Camera 3, we measure the rate of diffusion of stars through the core of the globular cluster 47 Tucanae using a sample of young white dwarfs identified in these observations. This is…

Solar and Stellar Astrophysics · Physics 2015-06-23 Jeremy Heyl , Harvey B. Richer , Elisa Antolini , Ryan Goldsbury , Jason Kalirai , Javiera Parada , Pier-Emmanuel Tremblay

We enhance the treatment of crystallization for models of white dwarfs (WDs) in the stellar evolution software MESA by implementing carbon-oxygen (C/O) phase separation. The phase separation process during crystallization leads to transport…

Solar and Stellar Astrophysics · Physics 2023-07-05 Evan B. Bauer

We report our study of features at the observed red end of the white dwarf cooling sequences for three Galactic globular clusters: NGC\,6397, 47\,Tucanae and M\,4. We use deep colour-magnitude diagrams constructed from archival Hubble Space…

Reliable modeling of the atmospheres of cool white dwarfs is crucial for understanding the atmospheric evolution of these stars and for accurate white dwarfs cosmochronology. Over the last decade {\it ab initio} modeling entered many…

Solar and Stellar Astrophysics · Physics 2015-05-20 Piotr M. Kowalski

We present a set of ultramassive white dwarf models, focused on masses above $1.3\,M_\odot$. Given the uncertainties about the formation and compositions of such objects, we construct parameterized model sequences, guided by evolutionary…

Solar and Stellar Astrophysics · Physics 2021-08-18 Josiah Schwab

We present a new set of cooling models and isochrones for both H- and He-atmosphere white dwarfs, incorporating accurate boundary conditions from detailed model atmosphere calculations, and carbon-oxygen chemical abundance profiles based on…

Solar and Stellar Astrophysics · Physics 2015-05-18 M. Salaris , S. Cassisi , A. Pietrinferni , P. M. Kowalski , J. Isern

With the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope, we have discovered in M4 (NGC 6121, C 1620-264) the first extensive sequence of cooling white dwarfs seen in a globular cluster. Adopting a distance modulus of…

We present full evolutionary calculations appropriate for the study of hydrogen-rich DA white dwarfs. This is done by evolving white dwarf progenitors from the zero age main sequence, through the core hydrogen burning phase, the helium…

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