J/ApJ/655/L33 High-resolution spectrum of OGLE-2006-BLG-265 (Johnson+, 2007)
A high-resolution spectrum of the extremely metal-rich bulge G dwarf
OGLE-2006-BLG-265.
Johnson J.A., Gal-Yam A., Leonard D.C., Simon J.D., Udalski A., Gould A.
<Astrophys. J., 655, L33-L36 (2007)>
=2007ApJ...655L..33J 2007ApJ...655L..33J
ADC_Keywords: Stars, dwarfs ; Spectroscopy
Keywords: Galaxy: abundances - Galaxy: bulge - Galaxy: evolution-
gravitational lensing - stars: abundances
Abstract:
We present an R=45000 Keck spectrum of the microlensed Galactic bulge
G dwarf OGLE-2006-BLG-265, which has high (∼60) signal-to-noise ratio
despite its short (15 minute) exposure time, because the source was
magnified by A∼135. While it is very metal-rich ([Fe/H]=0.56), the
higher temperature of this star compared with the luminous red giants
usually measured in the bulge gives its spectrum many unblended atomic
lines. We measure the abundances of 17 elements, including the first
abundances for S and Cu in a bulge star. The [alpha/Fe] ratios are
subsolar, while the odd-Z elements are slightly supersolar, trends
that are also seen in the more metal-rich stars in the bulge and the
local Galactic disk. Because the star is a dwarf, the [O/Fe], [Na/Fe],
and [Al/Fe] ratios cannot be attributed to internal mixing, as is
sometimes claimed for giants. Similar high-resolution spectra could be
obtained for about a dozen bulge dwarf stars per year by means of
well-designed target-of-opportunity observations.
Description:
We observed OGLE-2006-BLG-265 using the High Resolution Echelle
Spectrometer (HIRES) mounted on the Keck I 10m telescope on 2006 June
6 with a 600s exposure ending at 14:07:11 UT and a 300s second
exposure ending at 14:49:53 UT.
Objects:
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RA (2000) DE Designation(s)
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18 07 18.9 -27 47 43 OGLE-2006-BLG-265 = EWS 2006-BLG-265
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 41 501 Equivalent widths and line information
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Ion Ion designation
6- 13 F8.3 0.1nm lambda Wavelength
15- 19 F5.3 eV EP Energy potential
21- 26 F6.3 --- loggf Oscillator strength
28- 30 F3.1 --- Damp Damping factor (Correction factor to the
Unsoeld approximation)
32- 36 F5.1 0.1pm EW ? Equivalent width
37 A1 --- n_EW [b] b is treated as a blend
39- 41 I3 --- A ? Isotope number
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Dec-2008