Constraints on the distance moduli, helium and metal abundances, and ages of globular clusters from their RR Lyrae and non-variable horizontal-branch stars. II. Multiple stellar populations in 47Tuc, M3, and M13

Abstract

We present a new set of horizontal-branch (HB) models computed with the MESA stellar evolution code. The models adopt $\alpha$-enhanced \cite{ags09} metals mixtures and include the gravitational settling of He. They are used in our HB population synthesis tool to generate theoretical distributions of HB stars in order to describe the multiple stellar populations in the globular clusters 47Tuc, M3, and M13. The observed HB in 47Tuc is reproduced very well by our simulations for [Fe/H] $=-0.70$ and [$\alpha$/Fe] $=+0.4$ if the initial helium mass fraction varies by $\Delta Y_0\sim 0.03$ and approximately 21%, 37%, and 42% of the stars have $Y_0=0.257$, 0.270, and 0.287, respectively. These simulations yield $(m-M{)}_V=13.27$, implying an age near 13.0 Gyr. In the case of M3 and M13, our synthetic HBs for [Fe/H] $=-1.55$ and [$\alpha$/Fe] $=0.4$ match the observed ones quite well if M3 has $\Delta Y_0\sim 0.01$ and $(m-M{)}_V=15.02$, resulting in an age of 12.6 Gyr, whereas M13 has $\Delta Y_0\sim 0.08$ and $(m-M{)}_V=14.42$, implying an age of 12.9 Gyr. Mass loss during giant-branch evolution and $\Delta Y_0$ appear to be the primary second parameters for M3 and M13. New observations for 7 of the 9 known RR Lyrae in M13 are also reported. Surprisingly, periods predicted for the $c$-type variables tend to be too high (by up to $\sim 0.1$~d).

27 pages, 21 figures, 5 tables, accepted for publication in ApJ

References in corpus (23)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Fast rotating massive stars and the origin of the abundance patterns in galactic globular clusters
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. I. Overview of the Project and Detection of Multiple Stellar Populations
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• Synthetic Stellar Photometry - I. General considerations and new transformations for broad-band systems
• Systematic non-LTE study of the $-2.6\le$ [Fe/H] $\le 0.2$ F and G dwarfs in the solar neighbourhood. II. Abundance patterns from Li to Eu
• Iron and s-elements abundance variations in NGC5286: comparison with anomalous globular clusters and Milky Way satellites
• The fraction of second generation stars in Globular Clusters from the analysis of the Horizontal Branch
• Light nuclei in galactic globular clusters : constraints on the self-enrichment scenario from nucleosynthesis
• Iron and neutron-capture element abundance variations in the globular cluster M2 (NGC 7089)
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. II. The seven stellar populations of NGC7089 (M2)
• Mass loss on the red giant branch: the value and metallicity dependence of Reimers' η in globular clusters
• Isochrones for Old (> 5 Gyr) Stars and Stellar Populations. I. Models for $-2.4\le$ [Fe/H] $\le +0.6$, $0.25\le Y\le 0.33$, and $-0.4\le$ [$\alpha$\Fe] $\le +0.4$
• A new abundance scale for the globular cluster 47 Tuc
• Helium and Multiple Populations in the Massive Globular Cluster NGC6266 (M62)
• The primordial and evolutionary abundance variations in globular-cluster stars: a problem with two unknowns
• Constraints on Helium Enhancement in the Globular Cluster M3 (NGC 5272): The Horizontal Branch Test
• Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-Variable Horizontal-Branch Stars. I. M3, M15, and M92
• Lost and found: evidence of Second Generation stars along the Asymptotic Giant Branch of the globular cluster NGC 6752
• A Semi-Empirical Study of the Mass Distribution of Horizontal Branch Stars in M3 (NGC 5272)
• Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars. IV. Oxygen diagnostics in extremely metal-poor red giants with infrared OH lines
• A stellar population synthesis approach to the Oosterhoff dichotomy

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• Chemical Abundances Of Open Clusters From High-Resolution Infrared Spectra. I. NGC 6940
• Constraints on the Galactic Inner Halo Assembly History from the Age Gradient of Blue Horizontal-branch Stars
• Near-infrared Census of RR Lyrae variables in the Messier 3 globular cluster and the Period--Luminosity Relations
• Isochrone fitting of Galactic globular clusters -- II. NGC6205 (M13)
• Models for Metal-Poor Stars with Different Initial Abundances of C, N, O, Mg, and Si. II. Application to the Colour-Magnitude Diagrams of the Globular Clusters 47 Tuc, NGC 6362, M5, M3, M55, and M92
• Models of Metal-Poor Stars with Different Initial Abundances of C, N, O, Mg, and Si. I. Bolometric Corrections Derived from New MARCS Synthetic Spectra and Their Implications for Observed Colour-Magnitude Diagrams
• Multi-wavelength Photometric Study of RR Lyrae Variables in the Globular Cluster NGC 5272 (Messier 3)
• Models for Metal-Poor Stars with Different Initial Abundances of C, N, O, Mg, and Si. III. Grids of Isochrones for $-2.5\le$ [Fe/H] $\le -0.5$ and Helium Abundances $Y=0.25$ and $0.29$ at Each Metallicity
• On the maximum helium content of multiple populations in the globular cluster NGC6752
• Hubble Space Telescope Astrometry of the Metal-Poor Visual Binary $\mu$ Cassiopeiae: Dynamical Masses, Helium Content, and Age
• Globular Cluster UVIT legacy Survey (GlobUleS) III. Omega Centauri in Far-Ultraviolet
• Analysis of integrated-light spectra of Galactic globular clusters
• The GeMS/GSAOI Galactic Globular Cluster Survey (G4CS) II: Characterization of 47 Tuc with Bayesian Statistics
• Exploring the nature and synchronicity of early cluster formation in the Large Magellanic Cloud: III. Horizontal Branch Morphology
• Globular Cluster UVIT Legacy Survey (GlobULeS) $-$ II. Evolutionary status of hot stars in M3 and M13
• The role of mass loss in constraining quenching time in dwarf galaxies from AGB and RGB star counts
• Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)