The Cluster Ages Experiment (CASE). VIII. Age and Distance of the Globular Cluster 47 Tuc from the Analysis of Two Detached Eclipsing Binaries
| Autor: | P. Pietrukowicz, Radosław Poleski, Aaron Dotter, Jan Skowron, S. Kozlowski, Jennifer L. Marshall, Andrew McWilliam, Wojciech Pych, G. S. Burley, Yuri Beletsky, S. E. Persson, Andrzej Udalski, Michał K. Szymański, M. Rozyczka, P. Mróz, A. Schwarzenberg-Czerny, Krzysztof Ulaczyk, Łukasz Wyrzykowski, David J. Osip, Igor Soszyński, Ian B. Thompson, Nidia Morrell, Andrew J. Monson |
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| Rok vydání: | 2020 |
| Předmět: |
Binary number
globular clusters: individual (47 Tuc) FOS: Physical sciences Orbital eccentricity Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences 0103 physical sciences Cluster (physics) Astrophysics::Solar and Stellar Astrophysics Surface brightness 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Physics 010308 nuclear & particles physics Diagram binaries: eclipsing Astronomy and Astrophysics Orbital period Astrophysics - Astrophysics of Galaxies Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science stars: individual (V69 47 Tuc E32 47 Tuc) Globular cluster Astrophysics of Galaxies (astro-ph.GA) Astrophysics::Earth and Planetary Astrophysics binaries: spectroscopic |
| DOI: | 10.48550/arxiv.2001.01481 |
| Popis: | We use photometric and spectroscopic observations of the eclipsing binary E32 in the globular cluster 47 Tuc to derive the masses, radii, and luminosities of the component stars. The system has an orbital period of 40.9 d, a markedly eccentric orbit with e = 0.24, and is shown to be a member of or a recent escaper from the cluster. We obtain Mp = 0.862 ± 0.005 M, Rp = 1.183 ± 0.003 R, Lp = 1.65 ± 0.05 L for the primary and Ms = 0.827 ± 0.005 M, Rs = 1.004 ± 0.004 R, Ls = 1.14 ± 0.04 L for the secondary. Based on these data and on an earlier analysis of the binary V69 in 47 Tuc, we measure the distance to the cluster from the distance moduli of the component stars, and, independently, from a colour – surface brightness calibration. We obtain 4.55 ± 0.03 and 4.50 ± 0.07 kpc, respectively – values compatible within 1 σ with recent estimates based on Gaia DR2 parallaxes. By comparing the M–R diagram of the two binaries and the colour–magnitude diagram of 47 Tuc to Dartmouth model isochrones we estimate the age of the cluster to be 12.0 ± 0.5 Gyr, and the helium abundance of the cluster to be Y ≈ 0.25. Erratum published in volume 494, issue 1, pages 846-9, May 2020. DOI: 10.1093/mnras/staa686 |
| Databáze: | OpenAIRE |
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