J/A+A/465/815 Abundances of Sgr dSph stars (Sbordone+, 2007)
The exotic chemical composition of the Sagittarius dwarf spheroidal galaxy.
Sbordone L., Bonifacio P., Buonanno R., Marconi G., Monaco L., Zaggia S.
<Astron. Astrophys., 465, 815-824 (2007)>
=2007A&A...465..815S 2007A&A...465..815S
ADC_Keywords: Abundances, [Fe/H] ; Equivalent widths ; Clusters, globular ;
Stars, giant
Keywords: stars: abundances - stars: atmospheres - galaxies: abundances -
galaxies: dwarf - galaxies: individual: Sgr dSph -
globular clusters: individual: Terzan 7
Abstract:
The Sagittarius dwarf spheroidal galaxy is the nearest neighbor of the
Milky Way. Moving along a short period quasi-polar orbit within the
Halo, it is being destroyed by the tidal interaction with our Galaxy,
losing its stellar content along a huge stellar stream. We study the
detailed chemical composition of 12 giant stars in the Sagittarius
dwarf Spheroidal main body, together with 5 more in the associated
globular cluster Terzan 7, by means of high resolution VLT-UVES
spectra. Abundances are derived for up to 21 elements from O to Nd, by
fitting lines EW or line profiles against ATLAS 9 model atmospheres
and SYNTHE spectral syntheses calculated ad-hoc. Temperatures are
derived from (V-I)0 or (B-V)0 colors and gravities from
FeI-FeII ionization equilibrium. The metallicity of the observed stars
is between [Fe/H]=-0.9 and 0. We detected a highly peculiar "chemical
signature", with undersolar alpha elements, Na, Al , Sc, V, Co, Ni,
Cu, and Zn, among others, and overabundant La, Ce, and Nd. Many of
these abundance ratios (in particular light-odd elements and iron peak
ones) are strongly at odds with what is observed within the Milky Way,
so they may be a very useful tool for recognizing populations
originating within the Sagittarius dwarf. This can be clearly seen in
the case of the globular Palomar 12, which is believed to have been
stripped from Sagittarius: the cluster shows precisely the same
chemical "oddities", thus finally confirming its extragalactic
origin.
Description:
Tables A1-A3 of the paper detailing wavelengths, loggf, reference for
the atomic data, measured equivalent widths and derived abundances
for the 12 Sgr dSph stars and the 5 Ter 7 stars in the paper.
Objects:
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RA (2000) DE Designation(s)
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18 55 03.1 -30 28 42 Sgr dSph = NAME SGR DWARF GALAXY
19 17 43.7 -34 39 27 Ter7 = Cl Terzan 7
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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 17 Photometry and atmospheric parameters for the
studied stars
tablea.dat 41 2083 Equivalent widths and abundances
refs.dat 119 25 References
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See also:
J/A+A/414/503 : Abundances in the Sgr dSph (Bonifacio+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Parent Sgr or Ter7
6- 9 I4 --- Star Star number (G1)
11- 16 F6.3 mag Vmag V magnitude
18- 22 F5.3 mag (V-I)0 ? Dereddened V-I colour index (Sgr stars only)
24- 28 F5.3 mag (B-V)0 ? Dereddened B-V colour index (Ter7 stars only)
29- 32 I4 K Teff Effective temperature
34- 36 F3.1 [cm/s2] logg Surface gravity
38- 41 F4.2 km/s xi Turbulent velocity
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Byte-by-byte Description of file: tablea.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star Star number (G1)
6- 9 A4 --- Ion Ion name
11- 18 F8.4 nm Lambda Line laboratory wavelength (2)
20- 25 F6.3 --- loggf line oscillator strength
27- 30 A4 --- r_loggf References for employed loggf
32- 36 F5.2 pm EW ?=0.0 Equivalent width (3)
38- 41 F4.2 --- Abund ?=0.0 Abundance
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Note (2): Where HFS has been taken into account, the wavelength is provided
with 0.01nm precision only, for the feature is actually not a
single line.
Note (3): All "real" values are above 1.0pm here.
-- A value of 0.01 indicates that the abundance has been derived by
fitting agains a synthetic spectrum due to line blending.
-- A value of 0.02 indicates synthetic spectrum fitting taking into
account HFS.
-- A value of 0.0 indicates the line has not been measured for this
star. In this case the abundance is also put to 0.0.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Ref Reference code
6- 24 A19 --- BibCode BibCode
26- 45 A20 --- Aut Author's name
49-119 A71 --- Com Comments
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Blobal notes:
Note (G1): Nomenclature:
Stars 439 to 927 are Sgr dSph stars, [MBC98a] Sgr1 NNN in Simbad.
Stars 1272 to 1708 are Terzan 7 stars, Cl* Terzan 7 BCP NNNN in Simbad.
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Acknowledgements:
Luca Sbordone, luca.sbordone(at)obspm.fr
References:
Bonifacio et al., Paper I 2000A&A...359..663B 2000A&A...359..663B
Sbordone et al., Paper II 2005A&A...437..905S 2005A&A...437..905S
Bonifacio et al., Paper III 2004A&A...414..503B 2004A&A...414..503B, Cat. J/A+A/414/503
(End) Patricia Vannier [CDS] 12-Apr-2007