The evolution of isotope ratios in the Milky Way Galaxy

By C. Kobayashi, A. Karakas, H. Umeda. 2011

290 citations recorded by the source corpus.

Isotope ratios have opened a new window into the study of the details of stellar evolution, supernovae, and galactic chemical evolution. We present the evolution of the isotope ratios of elemental abundances (from C to Zn) in the solar neighbourhood, bulge, halo, and thick disk, using chemical evolution models with updated yields of Asymptotic Giant Branch (AGB) stars and core-collapse supernovae. The evolutionary history of each element is different owing to the effects of the initial progenitor mass and metallicity on element production. In the bulge and thick disk the star formation timescale is shorter than in the solar neighbourhood, leading to higher [�/Fe] ratios. Likewise, the smaller contribution from Type Ia supernovae in these regions leads to lower [Mn/Fe] ratios. Also in the bulge, the abundances of [(Na, Al, P, Cl, K, Sc, Cu, Zn)/Fe] are higher because of the effect of metallicity on element production from core-collapse supernovae. According to our predictions, it is possible to find metalrich stars ([Fe/H] > 1) that formed in the early Universe as a result of rapid star formation. The chemical enrichment timescale of the halo is longer than in the solar neighbourhood, and consequently the ratios of [(C, F)/Fe] and 12 C/ 13 C are higher owing to a significant contribution from low-mass AGB stars. While the [�/Fe] and [Mn/Fe] ratios are the same as in the solar neighbourhood, the [(Na, Al, P, Cl, K, Sc, Cu, Zn)/Fe] ratios are predicted to be lower. Furthermore, we predict that isotope ratios such as 24 Mg/ 25,26 Mg are larger because of the contribution from low-metallicity supernovae. Using isotopic ratios it is possible to select stars that formed in a system with a low chemical enrichment efficiency such as the satellite galaxies t hat were accreted onto our own Milky Way Galaxy.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/6b40ea215b047f8719013042af8088a51cb0c94f

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In Astronomy and Astrophysics

1. A. Karakas
2. A. Frebel
3. J. Norris
4. Timothy C. Beers
5. M. Lugaro
6. C. Kobayashi
7. J. Lattanzio
8. Nozomu Tominaga

Citations in the corpus

• Reconstructing the star formation history of the Milky Way disc(s) from chemical abundances (2014, background): “The choice of yields remains uncertain (Romano et al. 2010; Kobayashi et al. 2011, etc.).”
• The Dawes Review 2: Nucleosynthesis and Stellar Yields of Low- and Intermediate-Mass Single Stars (2014, methodology): “Kobayashi et al. (2011a) provide the most recent estimates of the chemical evolution of F using updated AGB yields as well as the latest ν-process yields from core-collapse SNe (see also Sánchez-Blázquez et al. 2012).”
• THE MOST METAL-POOR STARS. II. CHEMICAL ABUNDANCES OF 190 METAL-POOR STARS INCLUDING 10 NEW STARS WITH [Fe/H] ⩽ −3.5,, (2012, background): “We note in particular that the inclusion of yields from intermediate-mass stars cannot account for the underproduction of Na at low metallicity (Kobayashi et al. 2011b).”
• STELLAR YIELDS FROM METAL-RICH ASYMPTOTIC GIANT BRANCH MODELS (2016, background): “…under the assumption that the yields from previous generations of stars have contributed to the build up of elements over time (Romano et al. 2010; Kobayashi et al. 2011b,a; Shingles et al. 2014; Mollá et al. 2015) Theoretical nucleosynthesis calculations are also essential for a direct…”
• THE s-PROCESS IN ASYMPTOTIC GIANT BRANCH STARS OF LOW METALLICITY AND THE COMPOSITION OF CARBON-ENHANCED METAL-POOR STARS (2011, methodology): “…initial composition to: (1) the values predicted by galactic chemical evolution models for solar neighborhood stars of metallicity [Fe/H]=−2.3 from Kobayashi et al. (2011), this case affects only the initial composition of the elements up to Zn; (2) the values obtained assuming that the star was…”
• Super and massive AGB stars - IV. Final fates - Initial to final mass relation (2014, background): “…chemical evolution perspective due both to the substantial difference in nucleosynthetic products from intermediate-mass compared to massive stars (e.g Romano et al. 2010; Kobayashi et al. 2011), and to the differing contribution/feedback from supernova injecting their energy into the environment.”
• Astrophysics with Extraterrestrial Materials (2016, background): “F or p er so na l u se o nl y. mass functions (Timmes et al. 1995, Kobayashi et al. 2011) as well as the influence of heterogeneous mixing of stellar ejecta in the Galaxy (Lugaro et al. 1999).”
• Nucleosynthesis in Stars and the Chemical Enrichment of Galaxies (2013, methodology): “The ν process is included in Rauscher et al. (2002), Heger & Woosley (2010), Kobayashi et al. (2011).”
• Chemical evolution with rotating massive star yields - I. The solar neighbourhood and the s-process elements (2018, background): “This results in a very high 12C/13C ratio at low metallicity, of the order of several 103 (Prantzos et al. 1996; Kobayashi et al. 2011b; Chiappini et al. 2008), much higher than the solar value of ∼ 90.”