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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
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). 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:
FileName Lrecl Records Explanations
ReadMe 80 . This file catalog.dat 135 743 Stellar data param.dat 57 743 Stellar parameters
Byte-by-byte Description of file: catalog.dat
Bytes Format Units Label Explanations
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
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
Byte-by-byte Description of file: param.dat
Bytes Format Units Label Explanations
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)
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). One sigma lower and upper limits of Mv have been computed with π±σπ.
Acknowledgements: Caroline Soubiran, soubiran(at)obs.u-bordeaux1.fr
(End) C. Soubiran [Obs. Bordeaux], Patricia Vannier [CDS] 20-Apr-2005
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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