J/A+A/614/A149 417 Galactic bulge red giant O & Zn abund. (da Silveira+, 2018)
Oxygen and zinc abundances in 417 Galactic bulge red giant.
da Silveira C.R., Barbuy B., Friaca A.C.S., Hill V., Zoccali M.,
Rafelski M., Gonzalez O.A., Minniti D., Renzini A., Ortolani S.
<Astron. Astrophys. 614, A149 (2018)>
=2018A&A...614A.149D 2018A&A...614A.149D (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, giant ; Abundances
Keywords: Galaxy: bulge - Galaxy: abundances - stars: abundances
Abstract:
Oxygen and zinc in the Galactic bulge are key elements for the
understanding of the bulge chemical evolution. Oxygen-to-iron
abundance ratios provide a most robust indicator of the star formation
rate and chemical evolution of the bulge. Zinc is enhanced in
metal-poor stars, behaving as an α-element, and its production
may require nucleosynthesis in hypernovae. Most of the neutral gas at
high redshift is in damped Lyman-alpha systems (DLAs), where Zn is
also observed to behave as an α-element.
The aim of this work is the derivation of the α-element oxygen,
together with nitrogen, and the iron-peak element zinc abundances in
417 bulge giants, from moderate resolution (R∼22000) FLAMES-GIRAFFE
spectra. For stars in common with a set of UVES spectra with higher
resolution (R∼45000), the data are intercompared. The results are
compared with literature data and chemodynamical models.
We studied the spectra obtained for a large sample of red giant stars,
chosen to be one magnitude above the horizontal branch, using
FLAMES-GIRAFFE on the Very Large Telescope. We computed the O
abundances using the forbidden [OI] 6300.3Å and Zn abundances using
the ZnI 6362.34Å lines. Stellar parameters for these stars were
established in a previous work from our group.
We present oxygen abundances for 358 stars, nitrogen abundances for
403 stars and zinc abundances were derived for 333 stars. Having
oxygen abundances for this large sample adds information in particular
at the moderate metallicities of -1.6<[Fe/H]←0.8. Zn behaves as an
α-element, very similarly to O, Si, and Ca. It shows the same
trend as a function of metallicity as the α-elements, i.e., a
turnover around [Fe/H]~-0.6, and then decreasing with increasing
metallicity. The results are compared with chemodynamical evolution
models of O and Zn enrichment for a classical bulge. DLAs also show an
enhanced zinc-to-iron ratio, suggesting they may be enriched by
hypernovae.
Description:
The present data were obtained using the FLAMES- GIRAFFE instrument at
the 8.2 m Kueyen of the Very Large Telescope, at the European Southern
Observatory (ESO), in Paranal, Chile (ESO Projects 071.B-067,
071.B-0014; PI: A. Renzini). Targets are bulge K giants, with
magnitudes ∼1.0 above the red clump, originally in four fields.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 82 440 OGLE and GIRAFFE names, stellar parameters,
resulting [N/Fe], [O/Fe], [Zn/Fe], and
alpha-element abundances
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See also:
J/AcA/52/217 : OGLE II. VI photometry of Galactic Bulge (Udalski+, 2002)
J/A+A/486/177 : Bulge field stars from FLAMES-GIRAFFE spectra (Zoccali+, 2008)
J/A+A/530/A54 : Abundances of 650 bulge red giants (Gonzalez+, 2011)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- OGLE OGLE name (Udalski et al.,
2002AcA....52..217U 2002AcA....52..217U, Cat. J/AcA/52/217)
10 A1 --- n_OGLE [*] * for UVES data
12- 17 A6 --- GIRAFFE GIRAFFE name (Zoccali et al.,
2008A&A...486..177Z 2008A&A...486..177Z, Cat. J/A+A/486/177)
18 A1 --- n_GIRAFFE [*] * for UVES data
20- 23 I4 K Teff Effective Temperature
25- 28 F4.2 [cm/s2] logg Surface gravity
30- 34 F5.2 [-] [Fe/H] Metallicity
36- 38 F3.1 km/s vt Microturbulence velocity
40- 44 F5.2 [-] [N/Fe] ?=- [N/Fe] abundance
46 A1 --- l_[O/Fe] Limit flag on [O/Fe]
47- 51 F5.2 [-] [O/Fe] ?=- [O/Fe] abundance
52 A1 --- u_[O/Fe] [:] Uncertainty flag on [O/Fe]
54- 58 F5.2 [-] [Zn/Fe] ?=- [Zn/Fe] abundance
60- 64 F5.2 [-] [Mg/Fe] ?=- [Mg/Fe] abundance from Gonzalez et al.
(2011A&A...530A..54G 2011A&A...530A..54G, Cat. J/A+A/530/A54)
66- 70 F5.2 [-] [Si/Fe] ?=- [Sq/Fe] abundance from Gonzalez et al.
(2011A&A...530A..54G 2011A&A...530A..54G, Cat. J/A+A/530/A54)
72- 76 F5.2 [-] [Ce/Fe] ?=- [Ca/Fe] abundance from Gonzalez et al.
(2011A&A...530A..54G 2011A&A...530A..54G, Cat. J/A+A/530/A54)
78- 82 F5.2 [-] [Ti/Fe] ?=- [Ti/Fe] abundance from Gonzalez et al.
(2011A&A...530A..54G 2011A&A...530A..54G, Cat. J/A+A/530/A54)
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Acknowledgements:
Beatriz Barbuy, b.barbuy(at)iag.usp.br
(End) Patricia Vannier [CDS] 08-Mar-2018