J/MNRAS/488/2283 COMBS survey. Galactic Bulge metal-poor stars (Lucey+, 2019)
The COMBS survey. I: Chemical Origins of Metal-Poor Stars in the Galactic Bulge.
Lucey M., Hawkins K., Ness M., Asplund M., Bensby T., Casagrande L.,
Feltzing S., Freeman K.C., Kobayashi C., Marino A.F.
<Mon. Not. R. Astron. Soc. 488, 2283-2300 (2019)>
=2019MNRAS.488.2283L 2019MNRAS.488.2283L (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Stars, population II ; Abundances ; Radial velocities
Keywords: stars: abundances - stars: Population II - Galaxy: bulge -
Galaxy: evolution
Abstract:
Chemistry and kinematic studies can determine the origins of stellar
population across the Milky Way. The metallicity distribution function
of the bulge indicates that it comprises multiple populations, the
more metal-poor end of which is particularly poorly understood. It is
currently unknown if metal-poor bulge stars ([Fe/H]←1dex) are part of
the stellar halo in the inner most region, or a distinct bulge
population or a combination of these. Cosmological simulations also
indicate that the metal-poor bulge stars may be the oldest stars in
the Galaxy. In this study, we successfully target metal-poor bulge
stars selected using SkyMapper photometry. We determine the stellar
parameters of 26 stars and their elemental abundances for 22 elements
using R∼47000 VLT/UVES spectra and contrast their elemental properties
with that of other Galactic stellar populations. We find that the
elemental abundances we derive for our metal-poor bulge stars have
lower overall scatter than typically found in the halo. This indicates
that these stars may be a distinct population confined to the bulge.
If these stars are, alternatively, part of the inner-most distribution
of the halo, this indicates that the halo is more chemically
homogeneous at small Galactic radii than at large radii. We also find
two stars whose chemistry is consistent with second-generation
globular cluster stars. This paper is the first part of the Chemical
Origins of Metal-poor Bulge Stars (COMBS) survey that will
chemo-dynamically characterize the metal-poor bulge population.
Description:
Based on observations collected at the European Southern Observatory
under ESO programme: 089.B-069
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 86 36 Observational properties of our target stars
param.dat 290 26 Parameters (table A1)
abund.dat 47 3075 Line abundances (table A2)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 --- Star Star identification number
9- 24 A16 --- 2MASS 2MASS name (HHMMSSss=DDMMSSs)
26- 34 F9.5 deg RAdeg Right ascension (J2000)
36- 44 F9.5 deg DEdeg Declination (J2000)
46- 50 F5.2 deg GLON [] Galactic longitude
52- 57 F6.2 deg GLAT Galactic latitude
59- 63 F5.2 mag Gmag Gaia G magnitude
65- 66 I2 --- Nspec Number of co-added spectra
68- 73 F6.1 km/s RV Mean measured radial velocity of those spectra
75- 77 F3.1 km/s e_RV rms uncertainty on RV
79- 82 F4.2 km/s RVscatter Scatter between spectra
84- 86 I3 pix-1 SNRL Signal-to-noise ratio for the lower/blue chip
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Byte-by-byte Description of file: param.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 --- Star Star identification number
9- 13 F5.1 pix-1 SNRL Signal-to-noise ratio for lower chip
15- 20 F6.1 K Teff Effective temperature
22- 26 F5.1 K e_Teff Error on the effective temperature
28- 31 F4.2 [cm/s2] log(g) Surface gravity
33- 36 F4.2 [cm/s2] e_log(g) Error on the surface gravity
38- 41 F4.2 km/s vmicro Microturbulence velocity
43- 46 F4.2 km/s e_vmicro Error on the microturbulence velocity
48- 52 F5.2 --- [Fe/H] Metallicity
54- 57 F4.2 --- e_[Fe/H] Error on the metallicity
59- 62 F4.2 --- [Mg/Fe] ? Abundance [Mg/Fe]
64- 67 F4.2 --- e_[Mg/Fe] ? Error on abundance [Mg/Fe]
69- 73 F5.2 --- [Si/Fe] Abundance [Si/Fe]
75- 78 F4.2 --- e_[Si/Fe] Error on abundance [Si/Fe]
80- 83 F4.2 --- [Ca/Fe] ? Abundance [Ca/Fe]
85- 87 F3.1 --- e_[Ca/Fe] ? Error on abundance [Ca/Fe]
89- 92 F4.2 --- [Ti/Fe] ? Abundance [Ti/Fe]
94- 97 F4.2 --- e_[Ti/Fe] ? Error on abundance [Ti/Fe]
99-103 F5.2 --- [Mn/Fe] ? Abundance [Mn/Fe]
105-108 F4.2 --- e_[Mn/Fe] ? Error on abundance [Mn/Fe]
110-114 F5.2 --- [Co/Fe] ? Abundance [Co/Fe]
116-119 F4.2 --- e_[Co/Fe] ? Error on abundance [Co/Fe]
121-124 F4.2 --- [O/Fe] ? Abundance [O/Fe]
126-129 F4.2 --- e_[O/Fe] ? Error on abundance [O/Fe]
131-134 F4.2 --- [Li/Fe] ? Abundance [Li/Fe]
136-139 F4.2 --- e_[Li/Fe] ? Error on abundance [Li/Fe]
141-145 F5.2 --- [Cr/Fe] Abundance [Cr/Fe]
147-150 F4.2 --- e_[Cr/Fe] Error on abundance [Cr/Fe]
152-156 F5.2 --- [Cu/Fe] ? Abundance [Cu/Fe]
158-161 F4.2 --- e_[Cu/Fe] ? Error on abundance [Cu/Fe]
163-167 F5.2 --- [La/Fe] ? Abundance [La/Fe]
169-172 F4.2 --- e_[La/Fe] ? Error on abundance [La/Fe]
174-177 F4.2 --- [Al/Fe] ? Abundance [Al/Fe]
179-182 F4.2 --- e_[Al/Fe] ? Error on abundance [Al/Fe]
184-188 F5.2 --- [Na/Fe] ? Abundance [Na/Fe]
190-193 F4.2 --- e_[Na/Fe] ? Error on abundance [Na/Fe]
195-199 F5.2 --- [Ni/Fe] ? Abundance [Ni/Fe]
201-204 F4.2 --- e_[Ni/Fe] ? Error on abundance [Ni/Fe]
206-210 F5.2 --- [Ba/Fe] ? Abundance [Ba/Fe]
212-215 F4.2 --- e_[Ba/Fe] ? Error on abundance [Ba/Fe]
217-220 F4.2 --- [Sr/Fe] ? Abundance [Sr/Fe]
222-225 F4.2 --- e_[Sr/Fe] ? Error on abundance [Sr/Fe]
227-231 F5.2 --- [Y/Fe] ? Abundance [Y/Fe]
233-236 F4.2 --- e_[Y/Fe] ? Error on abundance [Y/Fe]
238-241 F4.2 --- [Eu/Fe] ? Abundance [Eu/Fe]
243-246 F4.2 --- e_[Eu/Fe] ? Error on abundance [Eu/Fe]
248-252 F5.2 --- [V/Fe] ? Abundance [V/Fe]
254-257 F4.2 --- e_[V/Fe] ? Error on abundance [V/Fe]
259-263 F5.2 --- [Sc/Fe] Abundance [Sc/Fe]
265-268 F4.2 --- e_[Sc/Fe] Error on abundance [Sc/Fe]
270-274 F5.2 --- [Zr/Fe] ? Abundance [Zr/Fe]
276-279 F4.2 --- e_[Zr/Fe] ? Error on abundance [Zr/Fe]
281-285 F5.2 --- [Nd/Fe] ? Abundance [Nd/Fe]
287-290 F4.2 --- e_[Nd/Fe] ? Error on abundance [Nd/Fe]
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Byte-by-byte Description of file: abund.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 --- Star Star identification number
9- 13 A5 --- El Element
15- 20 F6.1 0.1nm lambda Wavelength
22- 28 F7.3 [-] log(gf) Oscillator strength
30- 35 F6.3 eV chi Excitation potential
37- 41 F5.2 --- epsilon log(epsilon) abundance
43- 47 F5.2 --- NLTE ? NLTE correction
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Acknowledgements:
Madeline Lucey, m_lucey(at)utexas.edu
(End) Patricia Vannier [CDS] 23-Jun-2020