Searching for the Signatures of Terrestrial Planets in Solar Analogs

González-Hernández, J. I.; Israelian, G.; Santos, N. C.; Sousa, S.; Delgado-Mena, E.; Neves, V.; Udry, S.
Referencia bibliográfica

The Astrophysical Journal, Volume 720, Issue 2, pp. 1592-1602 (2010).

Fecha de publicación:
9
2010
Número de autores
7
Número de autores del IAC
3
Número de citas
111
Número de citas referidas
86
Descripción
We present a fully differential chemical abundance analysis using very high resolution (λ/δλ >~ 85, 000) and very high signal-to-noise (S/N ~800 on average) HARPS and UVES spectra of 7 solar twins and 95 solar analogs, of which 24 are planet hosts and 71 are stars without detected planets. The whole sample of solar analogs provides very accurate Galactic chemical evolution trends in the metallicity range -0.3 < [Fe/H] < 0.5. Solar twins with and without planets show similar mean abundance ratios. We have also analyzed a sub-sample of 28 solar analogs, 14 planet hosts, and 14 stars without known planets, with spectra at S/N ~850 on average, in the metallicity range 0.14 < [Fe/H] < 0.36, and find the same abundance pattern for both samples of stars with and without planets. This result does not depend on either the planet mass, from 7 Earth masses to 17.4 Jupiter masses, or the orbital period of the planets, from 3 to 4300 days. In addition, we have derived the slope of the abundance ratios as a function of the condensation temperature for each star and again find similar distributions of the slopes for both stars with and without planets. In particular, the peaks of these two distributions are placed at a similar value but with the opposite sign to that expected from a possible signature of terrestrial planets. In particular, two of the planetary systems in this sample, each of them containing a super-Earth-like planet, show slope values very close to these peaks, which may suggest that these abundance patterns are not related to the presence of terrestrial planets.
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Recientemente se han llevado a cabo varios análisis espectroscópicos de estrellas con planetas. Uno de los resultados más relevantes ha sido descubrir que las estrellas con planetas son en promedio más metálicas que las estrellas del mismo tipo espectral sin planetas conocidos (Santos, Israelian & Mayor 2001, A&A, 373, 1019; 2004, A&A, 415, 1153)

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Israelian