Search for associations containing young stars (SACY) - II. Chemical abundances of stars in 11 young associations in the solar neighborhood

The recently discovered coeval, moving groups of young stellar objects in the solar neighborhood represent invaluable laboratories for studying recent star formation and searching for high metallicity stars that can be included in future exo-planet surveys. In this study, we derived through an uniform and homogeneous method stellar atmospheric parameters and abundances for iron, silicium, and nickel in 63 post-T Tauri stars from 11 nearby young associations. We further compare the results with two different pre-main sequence (PMS) and main sequence (MS) star populations. The stellar atmospheric parameters and the abundances presented here were derived using the equivalent width of individual lines in the stellar spectra by assuming the excitation/ionization equilibrium of iron. Moreover, we compared the observed Balmer lines with synthetic profiles calculated for model atmospheres with a different line-formation code. We found that the synthetic profiles agree reasonably well with the observed profiles, although the Balmer lines of many stars are substantially filled-in, probably by chromospheric emission. Solar metallicity is found to be a common trend in all the nearby young associations studied. The low abundance dispersion within each association strengthens the idea that the origin of these nearby young associations is related to the nearby star-forming regions (SFR). Abundances of elements other than iron are consistent with previous results for Main Sequence stars in the solar neighborhood. The chemical characterization of the members of the newly found nearby young associations, performed in this study and intended to proceed in subsequent works, is essential to understanding and testing the context of local star formation and the evolutionary history of the galaxy.

[1]  D. Queloz,et al.  Spectroscopic parameters for 451 stars in the HARPS GTO planet search program - Stellar [Fe/H] and the frequency of exo-Neptunes , 2008, 0805.4826.

[2]  D. James,et al.  Chemical abundances in six nearby star-forming regions. Implications for galactic evolution and plan , 2008, 0801.2529.

[3]  Michael Perryman,et al.  Astronomical Applications of Astrometry: The Hipparcos and Tycho Catalogues , 2008 .

[4]  M. Sterzik,et al.  Search for associations containing young stars (SACY). I. Sample and searching method , 2006, astro-ph/0609258.

[5]  N. Santos,et al.  Chemical abundances for the transiting planet host stars OGLE-TR-10, 56, 111, 113, 132, and TrES-1. Abundances in different galactic populations , 2006, astro-ph/0606758.

[6]  Observatoire de Geneve,et al.  Spectroscopic metallicities for planet-host stars: Extending the samples , 2005, astro-ph/0504154.

[7]  J. Valenti,et al.  The Planet-Metallicity Correlation , 2005 .

[8]  Ben Zuckerman,et al.  The AB Doradus Moving Group , 2004 .

[9]  Ben Zuckerman,et al.  Young Stars Near the Sun , 2004 .

[10]  O. Paris,et al.  The photospheric abundances of active binaries. III. Abundance peculiarities at high activity levels , 2004, astro-ph/0406348.

[11]  Michael S. Bessell,et al.  New Members of the TW Hydrae Association, β Pictoris Moving Group, and Tucana/Horologium Association , 2003 .

[12]  Spain.,et al.  Spectroscopic [Fe/H] for 98 extra-solar planet-host stars. Exploring the probability of planet formation , 2003, astro-ph/0311541.

[13]  Thomas Bensby,et al.  Elemental abundance trends in the Galactic thin and thick disks as traced by nearby F and G dwarf stars , 2003 .

[14]  J. Kasting.  Evolution of a habitable planet , 2003 .

[15]  J. Lépine,et al.  Open issues in local star formation , 2003 .

[16]  B. Bazzanella,et al.  The Origin of the β Pictoris Moving Group , 2002 .

[17]  Michael S. Bessell,et al.  The β Pictoris Moving Group , 2001 .

[18]  J. Fulbright.  Abundances and Kinematics of Field Stars. II. Kinematics and Abundance Relationships , 2001, astro-ph/0110164.

[19]  N. Santos,et al.  The metal-rich nature of stars with planets , 2001, astro-ph/0105216.

[20]  B. Zuckerman,et al.  Dusty Debris around Solar-Type Stars: Temporal Disk Evolution , 2001, astro-ph/0103185.

[21]  B. E. Reddy,et al.  Parent Stars of Extrasolar Planets. VI. Abundance Analyses of 20 New Systems , 2000, astro-ph/0010197.

[22]  E. Covino,et al.  Search for young stars among ROSAT All-Sky Survey X-ray sources in and around the R CrA dark cloud ⋆ , 2000, astro-ph/0008095.

[23]  C. Torres,et al.  A New Association of Post-T Tauri Stars near the Sun , 2000, astro-ph/0005579.

[24]  E. Feigelson,et al.  The η Chamaeleontis Cluster: Origin in the Sco-Cen OB Association , 2000, astro-ph/0005583.

[25]  B. Zuckerman,et al.  Identification of a Nearby Stellar Association in theHipparcos Catalog: Implications for Recent, Local Star Formation , 2000, astro-ph/0002461.

[26]  E. Feigelson,et al.  High-Energy Processes in Young Stellar Objects , 1999 .

[27]  E. Feigelson,et al.  The η Chamaeleontis Cluster: A Remarkable New Nearby Young Open Cluster , 1999 .

[28]  R. Bouwens,et al.  A Look At Three Different Scenarios for Bulge Formation , 1998, astro-ph/9812193.

[29]  K. Fuhrmann.  Nearby stars of the Galactic disk and halo. III. , 1998 .

[30]  D. B. Navascués.  The Age of Beta Pic Type Stars: Vega, Fomalhaut, β Pic and HR4796 , 1998 .

[31]  A. McWilliam.  ABUNDANCE RATIOS AND GALACTIC CHEMICAL EVOLUTION , 1997 .

[32]  T. Forveille,et al.  X-ray and molecular emission from the nearest region of recent star formation. , 1997, Science.

[33]  G. González.  The stellar metallicity—giant planet connection , 1997 .

[34]  D. Padgett.  Atmospheric Parameters and Iron Abundances of Low-Mass Pre-Main-Sequence Stars in Nearby Star Formation Regions , 1996 .

[35]  P. Flower,et al.  Transformations from Theoretical Hertzsprung-Russell Diagrams to Color-Magnitude Diagrams: Effective Temperatures, B-V Colors, and Bolometric Corrections , 1996 .

[36]  Jack J. Lissauer,et al.  Formation of the Giant Planets by Concurrent Accretion of Solids and Gas , 1995 .

[37]  R. Kurucz.  ATLAS9 Stellar Atmosphere Programs and 2 km/s grid. , 1993 .

[38]  Michel Casse,et al.  Origin and evolution of the elements , 1993 .

[39]  N. Grevesse,et al.  In: Origin and Evolution of the elements , 1993 .

[40]  N. Grevesse,et al.  Abundances of the elements: Meteoritic and solar , 1989 .

[41]  L. V. Mirzoi︠a︡n.  Problems of physics and evolution of the universe = Вопросы физики и эволюции космса = Les Problémes de physique et d' évolution de l' universe , 1978 .