The Isotopic Abundances of Magnesium in Stars

@article{Gay2000TheIA,
  title={The Isotopic Abundances of Magnesium in Stars},
  author={P. L. Gay and David L. Lambert},
  journal={The Astrophysical Journal},
  year={2000},
  volume={533},
  pages={260 - 270}
}
Isotopic abundance ratios 24Mg : 25Mg : 26Mg are derived for 20 stars from high-resolution spectra of the MgH A-X 0-0 band at 5140 Å. With the exception of the weak G-band giant HR 1299, the stars are dwarfs that sample the metallicity range -1.8 < [Fe/H] < 0.0. The abundance of 25Mg and 26Mg relative to the dominant isotope 24Mg decreases with decreasing [Fe/H] in fair accord with predictions from a recent model of Galactic chemical evolution in which the Mg isotopes are synthesized by massive… 

Tables from this paper

Magnesium Isotopic Abundance Ratios in Cool Stars

From high-resolution spectra of 61 cool dwarfs and giants, Mg isotopic abundance ratios 24Mg : 25Mg : 26Mg are derived from spectral synthesis of the MgH A-X lines near 5140 Å. Our sample spans the

Magnesium Isotopes in Metal-poor Dwarfs: The Rise of AGB Stars and the Formation Timescale of the Galactic Halo

We have determined magnesium isotopic ratios (25, 26Mg/Mg) in metal-poor (-2.6 ≤ [Fe/H] ≤ -1.3) halo dwarfs employing high signal-to-noise ratio (S/N = 90-280), high spectral resolution (R = 105)

The Chemical Evolution of Magnesium Isotopic Abundances in the Solar Neighbourhood

Abstract The abundance of the neutron-rich magnesium isotopes observed in metal-poor stars is explained quantitatively with a chemical evolution model of the local Galaxy that considers — for the

Magnesium Isotope Ratios in Hyades Stars

Using classical model atmospheres and an LTE analysis, Mg isotope ratios 24Mg:25Mg:26Mg are measured in 32 Hyades dwarfs covering effective temperatures 4000 K ≤ Teff ≤ 5000 K. We find no significant

The cosmic evolution of magnesium isotopes

The abundance of magnesium in the interstellar medium is a powerful probe of star formation processes over cosmological time-scales. Magnesium has three stable isotopes, ^24Mg, ^25Mg, and ^26Mg,

Chemical evolution of Mg isotopes versus the time variation of the fine structure constant.

We show that the synthesis of (25,26)Mg at the base of the convective envelope in low-metallicity asymptotic giant branch stars can produce the isotopic ratios needed to explain the low-z subset

MAGNESIUM ISOTOPE RATIOS IN ω CENTAURI RED GIANTS

We have used the high-resolution observations obtained at the Anglo-Australian Telescope with Ultra-High Resolution Facility (R ∼ 100,000) and at Gemini-S with b-HROS (R ∼ 150,000) to determine

Mg Isotope Ratios in Giant Stars of the Globular Clusters M13 and M71

We present Mg isotope ratios in four red giants of the globular cluster M13 and one red giant of the globular cluster M71 based on high-resolution, high signal-to-noise ratio spectra obtained with

Mg isotopic ratios in giant stars of the globular cluster NGC 6752

Mg isotopic abundance ratios are measured in 20 bright red giants in globular cluster NGC 6752 based on very high-resolution (R 110 000), high signal-to-noise spectra obtained with UVES on the VLT.
...

References

SHOWING 1-10 OF 34 REFERENCES

Isotopic abundances of magnesium in five G and K dwarfs

High-resolution low-noise Reticon observations of MgH lines in the spectra of ..mu.. Cas, epsilon Eri, 61 Cyg A and B, and Gmb 1830 have been analyzed by spectrum synthesis. The mixtures of the

The Abundance of Lithium in Metal-poor Subgiant Stars

We have determined lithium abundances for a sample of 79 halo subgiants. The subgiant candidates were identified using uvby photometry from several catalogs of metal-poor stars. The basic data were

Rubidium in Metal-deficient Disk and Halo Stars

We report the first extensive study of stellar Rb abundances. High-resolution spectra have been used to determine, or set upper limits on, the abundances of this heavy element and the associated

Carbon and nitrogen abundances in metal-poor dwarfs of the solar neighborhood.

The authors have analyzed spectra of 83 subdwarfs for C, N, and Fe abundances. They deduced [C/Fe] from the CH bands (λ ≡ 4300 Å), [N/Fe] from the NH bands (λ ≡ 3360 Å), and [Fe/H] from strong mostly

Nitrogen overabundances in Population II dwarfs

From a survey and spectrum synthesis analysis of the NH features in the spectra of some 25 Population II dwarfs, two objects have been found in which nitrogen is overabundant relative to the heavy

Galacti chemical evolution: Hygrogen through zinc

Using the output from a grid of 60 Type II supernova models (Woosley & Weaver 1995) of varying mass (11 approx. less than (M/solar mass) approx. less than 40) and metallicity (0, 10(exp -4), 0.01,

Light-element abundances in the weak G-band star HR 6766

A high-resolution spectroscopic study of the weak G-band star HR 6766 has been carried out. Atomic line equivalent widths and broad-band photometric colors have been used to derive T/sub eff/=4750 +-

Estimation of Stellar Metal Abundance. II. A Recalibration of the Ca II K Technique, and the Autocorrelation Function Method

We have recalibrated a method for the estimation of stellar metal abundance, parameterized as [Fe/H], based on medium-resolution (1–2 Å) optical spectra (the majority of which cover the wavelength

The Evolution and Explosion of Massive Stars. II. Explosive Hydrodynamics and Nucleosynthesis

The nucleosynthetic yield of isotopes lighter than A = 66 (zinc) is determined for a grid of stellar masses and metallicities including stars of 11, 12, 13, 15, 18, 19, 20, 22, 25, 30, 35, and 40

Hydrostatic nucleosynthesis. I - Core helium and carbon burning.

The reaction network of the present examination of thermonuclear synthesis of nuclei during quasi-hydrostatic stages of the evolution of massive stars is complete up to atomic weight values of 74.