Paper: astro-ph/0512221
Date: Thu, 8 Dec 2005 15:11:22 GMT (163kb)

Title: Abundance ratios of volatile vs. refractory elements in
planet-harbouring stars: hints of pollution?

Authors: A. Ecuvillon (1), G. Israelian (1), N. C. Santos (2,3), M. Mayor (3),
G. Gilli (1,4) ((1) IAC, Spain, (2) Observatorio Astronomico de Lisboa,
Portugal, (3) Observatoire de Geneve, Switzerland, (4) Dipartimento di
Astronomia, Universita di Padova, Italy)

Comments: 10 pages, 7 figures, accepted for publication in A&A. Figures with
higher resolution are available at www.iac.es/proyect/abuntest
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We present the [X/H] trends as function of the elemental condensation
temperature Tc in 88 planet host stars and in a volume-limited comparison
sample of 33 dwarfs without detected planetary companions. We gathered
homogeneous abundance results for many volatile and refractory elements
spanning a wide range of Tc, from a few dozens to several hundreds kelvin. We
investigate possible anomalous trends of planet hosts with respect to
comparison sample stars in order to detect evidence of possible pollution
events. No significant differences are found in the behaviour of stars with and
without planets. This result is in agreement with a ``primordial'' origin of
the metal excess in planet host stars. However, a subgroup of 5 planet host and
1 comparison sample stars stands out for having particularly high [X/H] vs. Tc
slopes.

\\ ( http://arXiv.org/abs/astro-ph/0512221 , 163kb)

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Paper: astro-ph/0512222
Date: Thu, 8 Dec 2005 15:16:52 GMT (42kb)

Title: Condensation temperature trends among stars with planets

Authors: Guillermo Gonzalez

Comments: 5 pages, 7 figures, MNRAS Letter in press
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Results from detailed spectroscopic analyses of stars hosting massive planets
are employed to search for trends between abundances and condensation
temperatures. The elements C, S, Na, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni and
Zn are included in the analysis of 64 stars with planets and 33 comparison
stars. No significant trends are evident in the data. This null result suggests
that accretion of rocky material onto the photospheres of stars with planets is
not the primary explanation for their high metallicities. However, the
differences between the solar photospheric and meteoritic abundances do display
a weak but significant trend with condensation temperature. This suggests that
the metallicity of the sun's envelope has been enriched relative to its
interior by about 0.07 dex.

\\ ( http://arXiv.org/abs/astro-ph/0512222 , 42kb)