J/A+A/438/139 Abundances in Milky Way's disk (Soubiran+, 2005)
Abundance trends in kinematical groups of the Milky Way's disk.
Soubiran C., Girard P.
<Astron. Astrophys. 438, 139 (2005)>
=2005A&A...438..139S 2005A&A...438..139S
ADC_Keywords: Stars, fundamental ; Abundances, peculiar ; Space velocities
Keywords: stars: abundances - stars: kinematics - Galaxy: disk -
Galaxy: kinematics and dynamics - catalogs
Abstract:
We have compiled a large catalogue of metallicities and abundance
ratios from the literature in order to investigate abundance trends of
several alpha and iron peak elements in the thin disk and the thick
disk of the Galaxy. The catalogue includes 743 stars with abundances
of Fe, O, Mg, Ca, Ti, Si, Na, Ni and Al in the metallicity range
-1.30<[Fe/H]<+0.50. We have checked that systematic differences
between abundances measured in the different studies were lower than
random errors before combining them. Accurate distances and proper
motions from Hipparcos, and radial velocities from several sources
have been retrieved for 639 stars and their velocities (U,V,W) and
galactic orbits have been computed. Ages of 322 stars have been
estimated with the Bayesian method of isochrone fitting developed by
Pont & Eyer (2004MNRAS.351..487P 2004MNRAS.351..487P).
Two samples kinematically representative of the thin and thick disks
have been selected, taking into account the Hercules stream which is
intermediate in kinematics, but with a probable dynamical origin. Our
results show that the two disks are chemically well separated, they
overlap greatly in metallicity and both show parallel decreasing
trends of alpha elements with increasing metallicity, in the interval
-0.80<[Fe/H]←0.30. The Mg enhancement with respect to Fe of the thick
disk is measured to be 0.14dex. An even larger enhancement is observed
for Al. The thick disk is clearly older than the thin disk with a
tentative evidence of an AMR over 2-3Gyr and a hiatus in star
formation before the formation of the thin disk. We do not observe a
vertical gradient in the metallicity of the thick disk. The Hercules
stream have properties similar to that of the thin disk, with a wider
range of metallicity. Metal-rich stars assigned to the thick disk and
super metal rich stars assigned to the thin disk appear as outliers in
all their properties.
Description:
Abundances, kinematical and orbital parameters, ages, membership
probabilities in file 'catalog'. Atmospheric parameters, mean alpha
abundances and absolute magnitudes in file 'param'.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 135 743 Stellar data
param.dat 57 743 Stellar parameters
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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2- 12 A11 --- Star HD number (BD, CD, CPD, HIP, Giclas if missing)
14- 18 F5.2 Sun [Fe/H] Metallicity
20- 24 F5.2 Sun [O/Fe] ? Oxygen abundance relative to iron
26- 30 F5.2 Sun [Na/Fe] ? Sodium abundance relative to iron
32- 36 F5.2 Sun [Mg/Fe] ? Magnesium abundance relative to iron
38- 42 F5.2 Sun [Al/Fe] ? Aluminium abundance relative to iron
44- 48 F5.2 Sun [Si/Fe] Silicon abundance relative to iron
50- 54 F5.2 Sun [Ca/Fe] ? Calcium abundance relative to iron
56- 60 F5.2 Sun [Ti/Fe] ? Titanium abundance relative to iron
62- 66 F5.2 Sun [Ni/Fe] ? Nickel abundance relative to iron
68- 73 F6.1 km/s Uvel ? Galactic radial velocity (1)
75- 80 F6.1 km/s Vvel ? Galactic rotational velocity (1)
82- 87 F6.1 km/s Wvel ? Galactic vertical velocity (1)
89- 93 F5.2 kpc Rmin ? Perigalactic distance
95- 99 F5.2 kpc Rmax ? Apogalactic distance
101-105 F5.2 kpc Zmax ? Maximum distance from galactic plane
107-110 F4.2 -- ecc ? Eccentricity of galactic orbit
112-115 F4.1 Gyr age ? Age, in Gigayears
117-120 F4.2 % e_age ? Relative error on age
122-125 F4.2 % Pthin ? Thin disk membership probability
127-130 F4.2 % Pthick ? Thick disk membership probability
132-135 F4.2 % PHer ? Hercules stream membership probability
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Note (1): The three components of galactic velocity (U,V,W) are given with
respect to the Sun, the U axis pointing towards the Galactic Center
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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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2- 12 A11 --- Star HD number (BD, CD, CPD, HIP, Giclas if missing)
15- 18 I4 K Teff Effective temperature
21- 24 F4.2 [cm/s2] logg Gravity
26- 30 F5.2 Sun [Fe/H] Metallicity
32- 36 F5.2 Sun [alpha/Fe] Mean alpha abundance (1)
39- 43 F5.3 mag VMAG ? Absolute magnitude (2)
46- 50 F5.3 mag e_VMAG ? One sigma lower limit of Mv (2)
53- 57 F5.3 mag E_VMAG ? One sigma upper limit of Mv (2)
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Note (1): [alpha/Fe]=0.25*([Mg/Fe]+[Si/Fe]+[Ca/Fe]+[Ti/Fe])
Note (2): Absolute magnitudes are given for stars having an Hipparcos
parallax greater than 2mas and a relative error lower than 50%.
Apparent magnitudes have been deduced from Hipparcos magnitudes, Hp,
transformed into V Jonhson according to the calibration by Harmanec
(1998A&A...335..173H 1998A&A...335..173H). One sigma lower and upper limits of Mv have
been computed with π±σπ.
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Acknowledgements: Caroline Soubiran, soubiran(at)obs.u-bordeaux1.fr
(End) C. Soubiran [Obs. Bordeaux], Patricia Vannier [CDS] 20-Apr-2005