J/A+A/511/L10 Abundances and space velocities of 94 stars (Nissen+, 2010)
Two distinct halo populations in the solar neighborhood. Evidence from stellar
abundance ratios and kinematics.
Nissen P.E., Schuster W.J.
<Astron. Astrophys. 511, L10 (2010)>
=2010A&A...511L..10N 2010A&A...511L..10N
ADC_Keywords: Stars, nearby ; Abundances ; Space velocities
Keywords: stars: abundances - stars: kinematics - Galaxy: halo -
Galaxy: formation
Abstract:
Precise abundance ratios are determined for 94 dwarf stars with
5200<Teff<6300K, -1.6<[Fe/H]←0.4, and distances D≲335pc. Most of
them have halo kinematics, but 16 thick-disk stars are included.
Equivalent widths of atomic lines are measured from VLT/UVES and
NOT/FIES spectra with resolutions R∼55000 and R∼40000,
respectively. An LTE abundance analysis based on MARCS models is
applied to derive precise differential abundance ratios of Na, Mg, Si,
Ca, Ti, Cr, and Ni with respect to Fe.
Description:
Atmospheric parameters, abundance ratios, and space velocities are
given for halo and thick-disk stars observed with the ESO VLT/UVES and
NOT/FIES spectrographs at high resolution.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 74 94 Star list
table3.dat 97 53 Data based on VLT/UVES spectra
table4.dat 97 47 Data based on NOT/FIES spectra
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Simbad name
11 A1 --- m_Name Multiplicity index on Name
13- 14 I2 h RAh Simbad Hour of Right Ascension (J2000.0)
16- 17 I2 min RAm Simbad Minute of Right Ascension (J2000.0)
19- 22 F4.1 s RAs Simbad Second of Right Ascension (J2000.0)
24 A1 --- DE- Simbad Sign of the Declination (J2000.0)
25- 26 I2 deg DEd Simbad Degree of Declination (J2000.0)
28- 29 I2 arcmin DEm Simbad Arcminute of Declination (J2000.0)
31- 32 I2 arcsec DEs Simbad Arcsecond of Declination (J2000.0)
35- 40 F6.3 mag Bmag Simbad B band magnitude
42- 47 F6.3 mag Vmag Simbad V band magnitude
49- 56 A8 --- SpType Simbad MK spectral type
58- 65 A8 --- Inst Instrument used
67- 74 A8 --- Inst2 Second Instrument used
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Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Object name
11 A1 --- m_Name Multiplicty index on Name
13- 16 I4 K Teff Effective temperature
18- 21 F4.2 cm/s2 logg Logarithmic surface gravity
23- 27 F5.2 [Sun] [Fe/H] Iron-to-hydrogen ratio
29- 31 F3.1 km/s ksi Micro-turbulence velocity
33- 37 F5.2 [Sun] [Na/Fe] Sodium-to-iron ratio
39- 42 F4.2 [Sun] [Mg/Fe] Magnesium-to-iron ratio
44- 47 F4.2 [Sun] [Si/Fe] Silicon-to-iron ratio
49- 52 F4.2 [Sun] [Ca/Fe] Calcium-to-iron ratio
54- 57 F4.2 [Sun] [Ti/Fe] Titanium-to-iron ratio
59- 63 F5.2 [Sun] [Cr/Fe] Chromium-to-iron ratio
65- 69 F5.2 [Sun] [Ni/Fe] Nickel-to-iron ratio
71- 74 I4 km/s U(LSR) Galactic U-velocity component relative to LSR
76- 79 I4 km/s V(LSR) Galactic V-velocity component relative to LSR
81- 84 I4 km/s W(LSR) Galactiv W-velocity component relative to LSR
86- 97 A12 --- Class Population (1)
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Note (1): Classification of star as belonging to the thick-disk (TD), the
low-alpha halo, or the high-alpha halo population. For stars with
[Fe/H]←1.4, the classification is uncertain and given in parentheses.
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Acknowledgements:
Poul Erik Nissen, pen(at)phys.au.dk
(End) Poul Erik Nissen [Aarhus University], Patricia Vannier [CDS] 01-Mar-2010