Magnesium isotopes in metal-poor dwarfs: The rise of AGB stars and the formation timescale of the galactic halo

Jorge Meléndez; Judith G. Cohen

doi:10.1086/516735

Magnesium isotopes in metal-poor dwarfs: The rise of AGB stars and the formation timescale of the galactic halo

Jorge Meléndez^*, Judith G. Cohen

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

42 Citations (Scopus)

Abstract

We have determined magnesium isotopic ratios (^{25, 26}Mg/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 = 10 ⁵) Keck High Resolution Echelle Spectrometer (HIRES) spectra. Unlike previous claims of an important contribution from intermediate-mass asymptotic giant branch (AGB) stars at low metallicities, we find that the rise of the AGB contribution in the Galactic halo did not occur until intermediate metallicities ([Fe/H] ≳ -1.5).

Original language	English
Pages (from-to)	L25-L28
Journal	Astrophysical Journal
Volume	659
Issue number	1 II
DOIs	https://doi.org/10.1086/516735
Publication status	Published - 10 Apr 2007

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title = "Magnesium isotopes in metal-poor dwarfs: The rise of AGB stars and the formation timescale of the galactic halo",

abstract = "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 = 10 5) Keck High Resolution Echelle Spectrometer (HIRES) spectra. Unlike previous claims of an important contribution from intermediate-mass asymptotic giant branch (AGB) stars at low metallicities, we find that the rise of the AGB contribution in the Galactic halo did not occur until intermediate metallicities ([Fe/H] ≳ -1.5).",

keywords = "Galaxy: halo, Stars: AGB and post-AGB, Stars: abundances, Stars: atmospheres, Stars: population II",

author = "Jorge Mel{\'e}ndez and Cohen, \{Judith G.\}",

year = "2007",

month = apr,

day = "10",

doi = "10.1086/516735",

language = "English",

volume = "659",

pages = "L25--L28",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1 II",

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TY - JOUR

T1 - Magnesium isotopes in metal-poor dwarfs

T2 - The rise of AGB stars and the formation timescale of the galactic halo

AU - Meléndez, Jorge

AU - Cohen, Judith G.

PY - 2007/4/10

Y1 - 2007/4/10

N2 - 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 = 10 5) Keck High Resolution Echelle Spectrometer (HIRES) spectra. Unlike previous claims of an important contribution from intermediate-mass asymptotic giant branch (AGB) stars at low metallicities, we find that the rise of the AGB contribution in the Galactic halo did not occur until intermediate metallicities ([Fe/H] ≳ -1.5).

AB - 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 = 10 5) Keck High Resolution Echelle Spectrometer (HIRES) spectra. Unlike previous claims of an important contribution from intermediate-mass asymptotic giant branch (AGB) stars at low metallicities, we find that the rise of the AGB contribution in the Galactic halo did not occur until intermediate metallicities ([Fe/H] ≳ -1.5).

KW - Galaxy: halo

KW - Stars: AGB and post-AGB

KW - Stars: abundances

KW - Stars: atmospheres

KW - Stars: population II

UR - https://www.scopus.com/pages/publications/34248136518

U2 - 10.1086/516735

DO - 10.1086/516735

M3 - Article

SN - 0004-637X

VL - 659

SP - L25-L28

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 II

ER -

Magnesium isotopes in metal-poor dwarfs: The rise of AGB stars and the formation timescale of the galactic halo

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