Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity

Ghezzi, Luan; Cunha, Kátia; Smith, Verne V.; Araújo, F. X. de; Schuler, Simon C.; Reza, R. de la

doi:10.1088/0004-637x/720/2/1290

Cited by 188 publications

(211 citation statements)

References 60 publications

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“…This signature has been confirmed by further works (e.g. Fischer & Valenti 2005;Udry & Santos 2007;Ghezzi et al 2010) and may favor the theory of core-accretion for giant planet formation.…”

Section: Introductionsupporting

confidence: 74%

Signatures of Earth-Like Planets in the Chemical Composition of Solar-Type Stars

Meléndez

Ramírez

2012

Proc. IAU

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Abstract. The formation of terrestrial and gas giant planets has likely imprinted signatures on the chemical composition of their parent stars, as shown for example by the higher occurrence of giant planets for higher stellar metallicities. There are two new signatures that have been recently proposed by Meléndez et al. (2009Meléndez et al. ( , 2012 and Ramírez et al. (2009Ramírez et al. ( , 2010 for the formation of rocky planets, and by Ramírez et al. (2011) for gas giant planets. We review here our on-going work on the planet-star connection using solar twins, for which chemical abundances are being obtained at unprecedented precision (0.01 dex).

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Section: Introductionsupporting

confidence: 74%

Signatures of Earth-Like Planets in the Chemical Composition of Solar-Type Stars

Meléndez

Ramírez

2012

Proc. IAU

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“…Gonzalez 1997;Santos et al 2004;Fischer & Valenti 2005) and not in the case of exclusively low-mass planets (Ghezzi et al 2010;Mayor et al 2011;Sousa et al 2011b;Buchhave et al 2012).…”

Section: Metallicity Distributionsmentioning

confidence: 99%

“…Mayor et al 2011), seems to suggest that like planetesimals, low-mass planets may be abundant. Like stars with debris discs, stars hosting low-mass planets do not show the metal-rich signature seen in gas-giant main-sequence planet hosts (Ghezzi et al 2010;Mayor et al 2011;Sousa et al 2011b;Buchhave et al 2012). From the theoretical point of view, a strong correlation between the presence of cold dusty discs and low-mass planets is predicted (Raymond et al 2011(Raymond et al , 2012.…”

Section: Introductionmentioning

confidence: 98%

Searching for signatures of planet formation in stars with circumstellar debris discs

Maldonado

Eiroa

Villaver

et al. 2015

A&A

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Context. Tentative correlations between the presence of dusty circumstellar debris discs and low-mass planets have recently been presented. In parallel, detailed chemical abundance studies have reported different trends between samples of planet and non-planet hosts. Whether these chemical differences are indeed related to the presence of planets is still strongly debated. Aims. We aim to test whether solar-type stars with debris discs show any chemical peculiarity that could be related to the planet formation process. Methods. We determine in a homogeneous way the metallicity, [Fe/H], and abundances of individual elements of a sample of 251 stars including stars with known debris discs, stars harbouring simultaneously debris discs and planets, stars hosting exclusively planets, and a comparison sample of stars without known discs or planets. High-resolution échelle spectra (R ∼ 57 000) from 2−3 m class telescopes are used. Our methodology includes the calculation of the fundamental stellar parameters (T eff , log g, microturbulent velocity, and metallicity) by applying the iron ionisation and equilibrium conditions to several isolated Fe i and Fe ii lines, as well as individual abundances of C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn. Results. No significant differences have been found in metallicity, individual abundances or abundance-condensation temperature trends between stars with debris discs and stars with neither debris nor planets. Stars with debris discs and planets have the same metallicity behaviour as stars hosting planets, and they also show a similar [X/Fe] −T C trend. Different behaviour in the [X/Fe] −T C trends is found between the samples of stars without planets and the samples of planet hosts. In particular, when considering only refractory elements, negative slopes are shown in cool giant planet hosts, whilst positive ones are shown in stars hosting low-mass planets. The statistical significance of the derived slopes is low, however, probably because of the wide range of stellar parameters of our samples. Stars hosting exclusively close-in giant planets behave in a different way, showing higher metallicities and positive [X/Fe] −T C slope. A search for correlations between the [X/Fe] −T C slopes and the stellar properties reveals a moderate but significant correlation with the stellar radius and a weak correlation with the stellar age, which remain even if Galactic chemical evolution effects are considered. No correlation between the [X/Fe] −T C slopes and the disc/planet properties are found. Conclusions. The fact that stars with debris discs and stars with low-mass planets do not show either metal enhancement or a different [X/Fe] −T C trend might indicate a correlation between the presence of debris discs and the presence of low-mass planets. We extend results from previous works based mainly on solar analogues with reported differences in the [X/Fe] −T C trends between planet hosts and non-hosts to a wider range of parameters. However, these differences ...

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“…Udry et al 2006;Sousa et al 2008;Ghezzi et al 2010;Mayor et al 2011;Sousa et al 2011a). This gives us interesting hints about the planet formation processes.…”

Section: Introductionmentioning

confidence: 99%

Overabundance ofα-elements in exoplanet-hosting stars

Adibekyan

Santos

Sousa

et al. 2012

A&A

125

115

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We present the results for a chemical abundance analysis between planet-hosting and stars without planets for 12 refractory elements for a total of 1111 nearby FGK dwarf stars observed within the context of the HARPS GTO programs. Of these stars, 109 are known to harbour high-mass planetary companions and 26 stars are hosting exclusively Neptunians and super-Earths. We found that the [X/Fe] ratios for Mg, Al, Si, Sc, and Ti both for giant and low-mass planet hosts are systematically higher than those of comparison stars at low metallicities ([Fe/H] < ∼ from −0.2 to 0.1 dex depending on the element). The most evident discrepancy between planet-hosting and stars without planets is observed for Mg. Our data suggest that the planet incidence is greater among the thick disk population than among the thin disk for mettallicities bellow −0.3 dex. After examining the [α/Fe] trends of the planet host and non-host samples we conclude that a certain chemical composition, and not the Galactic birth place of the stars, is the determinating factor for that. The inspection of the Galactic orbital parameters and kinematics of the planet-hosting stars shows that Neptunian hosts tend to belong to the "thicker" disk compared to their high-mass planet-hosting counterparts. We also found that Neptunian hosts follow the distribution of high-α stars in the UW vs. V velocities space, but they are more enhanced in Mg than high-α stars without planetary companions. Our results indicate that some metals other than iron may also have an important contribution to planet formation if the amount of iron is low. These results may provide strong constraints for the models of planet formation, especially for planets with low mass.

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Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity

Cited by 188 publications

References 60 publications

Signatures of Earth-Like Planets in the Chemical Composition of Solar-Type Stars

Signatures of Earth-Like Planets in the Chemical Composition of Solar-Type Stars

Searching for signatures of planet formation in stars with circumstellar debris discs

Overabundance ofα-elements in exoplanet-hosting stars

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