Inhomogeneous chemical evolution of the Galactic disk

Malinie, G.; Hartmann, D. H.; Clayton, Donald D.; Mathews, Grant J.

doi:10.1086/173032

Cited by 57 publications

(102 citation statements)

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“…There is hovewer indirect way to test the reality of these predictions. The present-day oxygen abundance in the solar vicinity is 12 + log (O/H) = 8.50, and for the present-day gas mass fraction, 0.15 ÷ 0.20 appears to be a reasonable value (Malinie et al 1993). Figure 3 shows the O/H-µ diagram, where µ is the gas mass fraction.…”

Section: Verification Of the Validity Of The T E -Methods At High Metamentioning

confidence: 91%

Abundance determinations in H II regions

Pilyugin

2003

A&A

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Abstract. The discrepancy between the oxygen abundances in high-metallicity H  regions determined through the T e -method (and/or through the corresponding "strong lines -oxygen abundance" calibration) and that determined through the model fitting (and/or through the corresponding "strong lines -oxygen abundance" calibration) is discussed. It is suggested to use the interstellar oxygen abundance in the solar vicinity, derived with very high precision from the high-resolution observations of the weak interstellar OIλ1356 absorption lines towards the stars, as a "Rosetta stone" to verify the validity of the oxygen abundances derived in H  regions with the T e -method at high abundances. The agreement between the value of the oxygen abundance at the solar galactocentric distance traced by the abundances derived in H  regions through the T e -method and that derived from the interstellar absorption lines towards the stars is strong evidence in favor of that i) the two-zone model for T e seems to be a realistic interpretation of the temperature structure within H  regions, and ii) the classic T e -method provides accurate oxygen abundances in H  regions. It has been concluded that the "strong lines -oxygen abundance" calibrations must be based on the H  regions with the oxygen abundances derived with the T e -method but not on the existing grids of the models for H  regions.

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Section: Verification Of the Validity Of The T E -Methods At High Metamentioning

confidence: 91%

Abundance determinations in H II regions

Pilyugin

2003

A&A

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“…The validity of the IMA depends on the timescale of the mixing process. Malinie et al (1993) claim that due to chemical inhomogeneities in the disk, re-mixing and star formation may be delayed by 10 8−9 yr. We will include the consideration of delayed mixing in our calculations and inspect the influence of different mixing timescales on the observational constraints discussed above.…”

Section: Delayed Mixingmentioning

confidence: 99%

Stellar Yields and Chemical Evolution -- I. Abundance Ratios and Delayed Mixing in the Solar Neighbourhood

Thomas¹,

Greggio

Bender

1998

Monthly Notices of the Royal Astronomical Society

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We analyse two recent computations of type II supernova nucleosynthesis by Woosley & Weaver (1995, hereafter WW95) and Thielemann, Nomoto, & Hashimoto (1996, hereafter TNH96), focusing on the ability to reproduce the observed [Mg/Fe]-ratios in various galaxy types. We show that the yields of oxygen and total metallicity are in good agreement. However, TNH96-models produce more magnesium in the intermediate and less iron in the upper mass range of type II supernovae than WW95-models. To investigate the significance of these discrepancies for chemical evolution, we calculate Simple Stellar Population-yields for both sets of models and different IMF slopes. We conclude that the Mg-yields of WW95 do not suffice to explain the [Mg/Fe] overabundance neither in giant elliptical galaxies and bulges nor in metal-poor stars in the solar neighbourhood and the galactic halo. Calculating the chemical evolution in the solar neighbourhood according to the standard infall-model (e.g. Matteucci & Greggio 1986; Timmes, Woosley, & Weaver 1995; Yoshii, Tsujimoto, & Nomoto 1995), we find that using WW95 and TNH96 nucleosynthesis, the solar magnesium abundance is underestimated by 29 and 7 per cent, respectively.We include the relaxation of the instantaneous mixing approximation in chemical evolution models by splitting the gas component into two different phases. In additional simulations of the chemical evolution in the solar neighbourhood, we discuss various timescales for the mixing of the stellar ejecta with the interstellar medium. We find that a delay of the order of 10 8 years leads to a better fit of the observational data in the [Mg/Fe]-[Fe/H] diagram without destroying the agreement with solar element abundances and the age-metallicity relation.

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“…As a reference, we return to the standard Simple Model (e.g., Tinsley 1980;Pagel & Patchett 1975;Schmidt 1963), which assumes (a) a closed system that is (b) initially metal-free; (c) a constant stellar initial mass function (IMF); and (d) chemical homogeneity at all times. Most previous analytic investigations of inhomogeneous evolution were tied to the Simple Model and assumed a given dispersion in metal production: Tinsley (1975) adopted a fixed metallicity dispersion and propagated this through the Simple Model, while Searle (1977) and Malinie et al (1993) considered an ensemble of regions that individually follow the Simple Model such that they yield a given dispersion.…”

Section: Introductionmentioning

confidence: 99%

“…These become progressively narrower (eq. Malinie et al (1993) emphasize the importance of reproducing not only the low-metallicity tail but also the highmetallicity drop-off of the MDF. The Simple Model deviates most strongly from the data, illustrating the "G dwarf problem."…”

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confidence: 97%

A New Look at Simple Inhomogeneous Chemical Evolution

Oey

2000

The Astrophysical Journal

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A rudimentary, one-zone, closed-box model for inhomogeneous chemical evolution is offered as an alternative reference model, distinct from the Simple Model, in the limit of no mixing. The metallicity distribution functions (MDFs) of Galactic halo and bulge stars can be matched by varying a single evolutionary parameter, nQ. Q is the filling factor of contaminating regions, and n is the number of star-forming generations. Therefore, Q and n have equivalent roles, and combinations of n and Q yield systems with different metallicities at any given age. The model also revises the interpretation of observed MDFs. Unevolved systems probe the metallicity distribution of parent f (z) enrichment events; for example, the high-metallicity tail of the halo distribution agrees with a power-law . f (z)

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Inhomogeneous chemical evolution of the Galactic disk

Cited by 57 publications

References 0 publications

Abundance determinations in H II regions

Abundance determinations in H II regions

Stellar Yields and Chemical Evolution -- I. Abundance Ratios and Delayed Mixing in the Solar Neighbourhood

A New Look at Simple Inhomogeneous Chemical Evolution

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