J/ApJ/709/447 Chemical composition of OGLE-2007-BLG-514S (Epstein+, 2010)
Chemical composition of faint (I ∼ 21 mag) microlensed bulge dwarf
OGLE-2007-BLG-514S.
Epstein C.R., Johnson J.A., Dong S., Udalski A., Gould A., Becker G.
<Astrophys. J., 709, 447-457 (2010)>
=2010ApJ...709..447E 2010ApJ...709..447E
ADC_Keywords: Equivalent widths ; Abundances ; Gravitational lensing ;
Stars, G-type ; Spectroscopy ; Milky Way
Keywords: Galaxy: bulge - Galaxy: evolution - gravitational lensing: micro -
stars: abundances
Abstract:
We present a high-resolution spectrum of a microlensed G dwarf in the
Galactic bulge with spectroscopic temperature Teff=5600±180K. This
I∼21mag star was magnified by a factor ranging from 1160 to 1300 at
the time of observation. Its high metallicity ([Fe/H]=0.33±0.15dex)
places this star at the upper end of the bulge giant metallicity
distribution. Using a Kolmogorov-Smirnov test, we find a 1.6%
probability that the published microlensed bulge dwarfs share an
underlying distribution with bulge giants, properly accounting for a
radial bulge metallicity gradient. We obtain abundance measurements
for 15 elements and perform a rigorous error analysis that includes
covariances between parameters. This star, like bulge giants with the
same metallicity, shows no alpha enhancement. It confirms the chemical
abundance trends observed in previously analyzed bulge dwarfs. At
supersolar metallicities, we observe a discrepancy between bulge giant
and bulge dwarf Na abundances.
Description:
OGLE-2007-BLG-514S is located toward the Galactic bulge (J2000
RA=17h58m3.s09, DE=-27°31'05.7"; l=2.62, b=-1.63). Michael Rauch
and George Becker took three high-resolution spectra of
OGLE-2007-BLG-514S with the Magellan Inamori Kyocera Echelle (MIKE)
double spectrograph mounted on the Clay telescope at Las Campanas. The
slit was 1" wide, giving a resolution of 25000. We use only the red
side of the spectrograph, covering the wavelength range 9300-4900Å.
Objects:
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RA (2000) DE Designation(s)
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17 58 03.00 -27 31 08.2 OGLE-2007-BLG-514S = EWS 2007-BLG-514
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 48 206 Line parameters and equivalent widths
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See also:
J/A+A/533/A134 : Abundances of microlensed stars in the Bulge (Bensby+, 2011)
J/A+A/512/A41 : Abundances of microlensed stars in the Bulge (Bensby+, 2010)
J/A+A/499/737 : Abundances of microlensed dwarf and subgiant stars (Bensby+,
2009)
J/ApJ/699/66 : Abundances in two Galactic bulge stars (Cohen+, 2009)
J/ApJ/682/1029 : Abundances in OGLE-2007-BLG-349S (Cohen+, 2008)
J/ApJ/655/L33 : High-resolution spectrum of OGLE-2006-BLG-265 (Johnson+, 2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Name Atomic species name
9- 16 F8.3 0.1nm lambda Wavelength in Angstroms
19- 22 F4.2 eV EP Excitation potential
24- 29 F6.3 [-] log(gf) Log of the oscillator strength
34- 38 F5.1 10-13m Wstar ? OGLE-2007-BLG-514S equivalent width (mÅ)
40 A1 --- f_Wstar [s] eq.width from synthetic spectra (1)
42- 46 F5.1 10-13m Wsun ? Solar equivalent width (mÅ)
48 A1 --- f_Wsun [s] eq.width from synthetic spectra (1)
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Note (1): s = Abundance derived by comparison with synthetic spectra.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 02-Mar-2012