Bibcode
Delgado Mena, E.; Israelian, G.; González-Hernández, J. I.; Santos, N. C.; Rebolo, R.
Bibliographical reference
The Astrophysical Journal, Volume 746, Issue 1, article id. 47 (2012).
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2012
Journal
Citations
18
Refereed citations
15
Description
We present new Ultraviolet and Visual Echelle Spectrograph (UVES)
spectra of a sample of 15 cool unevolved stars with and without detected
planetary companions. Together with previous determinations, we study Be
depletion and possible differences in Be abundances between the two
groups of stars. We obtain a final sample of 89 and 40 stars with and
without planets, respectively, which covers a wide range of effective
temperatures, from 4700 K to 6400 K, and includes several cool dwarf
stars for the first time. We determine Be abundances for these stars and
find that for most of them (the coolest ones) the Be II resonance lines
are often undetectable, implying significant Be depletion. While for hot
stars Be abundances are approximately constant, with a slight fall as T
eff decreases and the Li-Be gap around 6300 K, we find a
steep drop of Be content as T eff decreases for T
eff < 5500 K, confirming the results of previous papers.
Therefore, for these stars there is an unknown mechanism destroying Be
that is not reflected in current models of Be depletion. Moreover, this
strong Be depletion in cool objects takes place for all the stars
regardless of the presence of planets; thus, the effect of extra Li
depletion in solar-type stars with planets when compared with stars
without detected planets does not seem to be present for Be, although
the number of stars at those temperatures is still small to reach a
final conclusion.
Based on observations made with UVES at VLT Kueyen 8.2 m telescope
at the European Southern Observatory (Cerro Paranal, Chile) in program
86.D-0082A.
Related projects
Observational Tests of the Processes of Nucleosynthesis in the Universe
Several spectroscopic analyses of stars with planets have recently been carried out. One of the most remarkable results is that planet-harbouring stars are on average more metal-rich than solar-type disc stars. Two main explanations have been suggested to link this metallicity excess with the presence of planets. The first of these, the “self
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