The Chemical Composition Contrast between M3 and M13 Revisited: New Abundances for 28 Giant Stars in M3

By C. Sneden, R. P. Kraft, P. Guhathakurta, R. Peterson, Jon P. Fulbright. 2003

161 citations recorded by the source corpus.

We report new chemical abundances of 23 bright red giant members of the globular cluster M3, based on high-resolution (R ∼ 45,000) spectra obtained with the Keck I telescope. The observations, which involve the use of multislits in the HIRES Keck I spectrograph, are described in detail. Combining these data with a previously reported small sample of M3 giants obtained with the Lick 3 m telescope, we compare metallicities and [X/Fe] ratios for 28 M3 giants with a 35-star sample in the similar-metallicity cluster M13, and with Galactic halo field stars having [Fe/H] < -1. For elements having atomic number A ≥ A(Si), we derive little difference in [X/Fe] ratios in the M3, M13, or halo field samples. All three groups exhibit C depletion with advancing evolutionary state beginning at the level of the red giant branch "bump," but the overall depletion of about 0.7–0.9 dex seen in the clusters is larger than that associated with the field stars. The behaviors of O, Na, Mg, and Al are distinctively different among the three stellar samples. Field halo giants and subdwarfs have a positive correlation of Na with Mg, as predicted from explosive or hydrostatic carbon burning in Type II supernova sites. Both M3 and M13 show evidence of high-temperature proton-capture synthesis from the ON, NeNa, and MgAl cycles, while there is no evidence for such synthesis among halo field stars. But the degree of such extreme proton-capture synthesis in M3 is smaller than it is in M13: the M3 giants exhibit only modest deficiencies of O and corresponding enhancements of Na, less extreme overabundances of Al, fewer stars with low Mg and correspondingly high Na, and no indication that O depletions are a function of advancing evolutionary state, as has been claimed for M13. We have also considered NGC 6752, for which Mg isotopic abundances have been reported by Yong et al. Giants in NGC 6752 and M13 satisfy the same anticorrelation of O abundances with the ratio (25Mg + 26Mg)/24Mg, which measures the relative contribution of rare to abundant isotopes of Mg. This points to a scenario in which these abundance ratios arose in the ejected material of 3–6 M⊙ cluster stars, material that was then used to form the atmospheres of the presently evolving low-mass cluster stars. It also suggests that the low oxygen abundance seen among the most evolved M13 giants arose in hot bottom O-to-N processing in these same intermediate-mass cluster stars. Thus, mixing is required by the dependence of some abundance ratios on luminosity, but an earlier nucleosynthesis process in a hotter environment than giants or main-sequence stars is required by the variations previously seen in stars near the main sequence. The nature and the site of the earlier process is constrained but not pinpointed by the observed Mg isotopic ratio.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/e97afeda779f6bc4d53568b7b44d22e6f38023db

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In Astronomy and Astrophysics

1. R. Gratton
2. E. Carretta
3. A. Bragaglia
4. Timothy C. Beers
5. F. D’Antona
6. Jay Anderson
7. G. Piotto
8. C. Sneden

In Electrical and Electronic Engineering

1. A. Sarajedini
2. Aaron Dotter
3. Jay Anderson
4. F. D’Antona
5. P. Ventura
6. Jorge Meléndez
7. R. Gratton
8. J. Cohen

In Instrumentation

1. R. Gratton
2. E. Carretta
3. A. Bragaglia
4. F. D’Antona
5. Timothy C. Beers
6. Jay Anderson
7. G. Piotto
8. A. Milone

Citations in the corpus

• Abundances In Very Metal-Poor Dwarf Stars (2004, background): “…spectra of large samples of stars in M71 ([Fe/H] = −0.7 dex) (Ramı́rez et al. 2001), M5 ([Fe/H] = −1.3 dex) (Ramı́rez & Cohen 2003) M3 ([Fe/H] = −1.45 dex) (Sneden et al. 2004; Cohen & Melendez 2004), 47 Tuc ([Fe/H] = −0.67 dex) (Carretta et al. 2004), and NGC 6397 ([Fe/H] = −2.02 dex)(Thévenin…”
• Massive AGB models of low metallicity: the implications for the self-enrichment scenario in metal-poor globular clusters (2009, background): “A similar aluminum enhancement was also detected by Sneden et al. (2004) in giants of low and high gravity in the two GCs M3 and M13.”
• Rotational mixing in low-mass stars: II. Self-consistent models of Pop II RGB stars (2006, methodology): “We model a typical metal-poor globular cluster RGB star with initial mass M = 0.85 M , initial helium content Yini = 0.248, and [Fe/H] = −1.57 which corresponds to the metallicity of M 13 stars (Sneden et al. 2004).”
• Full computation of massive AGB evolution. I. The large impact of convection on nucleosynthesis (2004, methodology): “Since our purpose is to test how the uncertainties connected with convection may reflect on the plausibility of the “selfenrichment” scenario, we adopt a chemistry which is typical of those GCs which show most of self-enrichment like M13, NGC6752 (Gratton et al. 2001, Sneden et al. 2004), i.e.”
• THE SEGUE STELLAR PARAMETER PIPELINE. II. VALIDATION WITH GALACTIC GLOBULAR AND OPEN CLUSTERS (2007, background): “Sneden et al. (2004) obtained [Fe/H] = −1.62 (from Fe i lines) and [Fe/H] = −1.55 (from Fe ii lines), based on a sample of stars observed with the KECK/HIRES spectrograph (R ∼ 45,000).”
• Abundances in giant stars of the globular cluster NGC 6752 (2005, unknown): “While our list of clusters is not as extensive as Sneden et al. (2004a), we do include all clusters with more than 10 stars analyzed.”
• THE AGES OF 55 GLOBULAR CLUSTERS AS DETERMINED USING AN IMPROVED METHOD ALONG WITH COLOR–MAGNITUDE DIAGRAM CONSTRAINTS, AND THEIR IMPLICATIONS FOR BROADER ISSUES (2013, background): “…13 (Johnson & Pilachowski 2012, Kraft et al. 1997), probably due to rotation-driven deep mixing, while such correlations are not seen in M 3 giants (Sneden et al. 2004, Cohen & Meléndez 2005a), may be telling us that cluster-to-cluster variations in the rotational properties of their stellar…”
• Abundance patterns of multiple populations in globular clusters: a chemical evolution model based on yields from AGB ejecta (2010, background): “In most GCs the O–depletion is limited to <∼ 0.8 dex, but we do know that giants in clusters like M 13 (Sneden et al. 2004) or NGC 2808 (Carretta et al. 2008) show extreme stars with oxygen depletion down to a factor larger than 20.”
• HIGH-RESOLUTION SPECTROSCOPY OF EXTREMELY METAL-POOR STARS IN THE LEAST EVOLVED GALAXIES: URSA MAJOR II and COMA BERENICES (2009, background): “In clusters, it has been found that the stars closest to the red giant branch tip have the highest Na abundances (up to [Na/Fe] ∼ 1.0; Sneden et al. 2004 and references therein).”
• Na-O anticorrelation and HB - VIII. Proton-capture elements and metallicities in 17 globular clusters from UVES spectra (2009, background): “While a range in polluter masses seem indeed present in clusters like NGC 3201 or NGC 6254 (or NGC 5272=M 3: see Sneden et al. 2004), the sequences seem almost monoparametric in other clusters, including NGC 104 (47 Tuc), NGC 2808, NGC 6752 (see also Yong et al. 2003), or NGC 6205 (M 13, see Sneden…”
• THE SEGUE STELLAR PARAMETER PIPELINE. IV. VALIDATION WITH AN EXTENDED SAMPLE OF GALACTIC GLOBULAR AND OPEN CLUSTERS (2010, methodology): “Our estimate of the cluster’s mean radial velocity, 〈RV〉 = −141.2 km s−1 ± 5.6, is slightly different those from Harris (1996) and Cohen & Meléndez (2005), who both report the same value (−147.6 km s−1), and Sneden et al. (2004) who reported a mean RV of −149.4 km s−1.”
• Formation and dynamical evolution of multiple stellar generations in globular clusters (2008, background): “In an analysis of the relative magnitude locations of the turnoff, red giant “bump” and HB, Caloi & D’Antona (2005) have provocatively suggested this possibility for M 13, the cluster showing the broadest range of chemical anomalies (Sneden et al. 2004).”
• The Effective Temperature Scale of FGK Stars. I. Determination of Temperatures and Angular Diameters with the Infrared Flux Method (2005, unknown): “The technique has been applied to a wide variety of samples: stars in the thin and thick disks of the Galaxy (Bensby et al. 2003, hereafter B03), planet-hosting stars (Santos et al. 2004, hereafter SIM04), globular cluster stars (Sneden et al. 2004), and so on.”
• On the self-enrichment scenario of galactic globular clusters: constraints on the IMF (2006, background): “Regarding the O-depletion levels, NGC 2808 is very similar to M13 (Sneden et al. 2004); both clusters display the most severe variations reported up to now.”
• A catalogue of masses, structural parameters, and velocity dispersion profiles of 112 Milky Way globular clusters (2018, unknown): “…et al. (2017) LOS NGC 5053 Abolfathi et al. (2017) LOS NGC 5139 Kunder et al. (2017) LOS Kamann et al. (2018) LOS NGC 5272 Marconi et al. (1998) MF Sneden et al. (2004) LOS Abolfathi et al. (2017) LOS NGC 5466 Abolfathi et al. (2017) LOS NGC 5634 Carretta et al. (2017) LOS Abolfathi et al.…”
• Near-Ultraviolet Observations of HD 221170: New Insights into the Nature of r-Process-rich Stars (2006, background): “…these lines are features we have employed in other high resolution abundance studies of globular cluster red giant stars (e.g., Ivans et al. 2001; Sneden et al. 2004; Johnson, Ivans & Stetson 2005), rprocess-enriched metal-poor stars such as BD+17◦3248 and CS 22892-052 (e.g., Cowan et al. 2002;…”