On the origin of stars with and without planets

Adibekyan, V.; Hernández, J. I. González; Delgado-Mena, E.; Sousa, S. G.; Santos, N. C.; Israelian, G.; Figueira, P.; Lis, S. Bertrán de

doi:10.1051/0004-6361/201423435

Cited by 95 publications

(154 citation statements)

References 45 publications

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“…It is commonly assumed that individual components in binary systems share the same origin and initial bulk abundances because they form within the same cloud. Therefore, under the reasonable assumption that the XO-2 components were born together from the same molecular cloud, their dissimilar elemental abundances seem to favor other explanations than Galactic chemical evolution and/or stellar birthplace effects as possible reasons of the abundance patterns we observe (see, e.g., Adibekyan et al 2014).…”

Section: Origin Of the Elemental Abundances Differencementioning

confidence: 73%

“…Any trend of [X/H] with T C can be quantified in terms of a positive slope in a linear fit. The possibility of a trend of [X/H] with T C (Sozzetti et al 2006;González Hernández et al 2013;Liu et al 2014;Mack et al 2014, and references therein) and its dependence on stellar age, surface gravity, and mean Galactocentric distance (Adibekyan et al 2014) has been investigated by several authors, and often no statistically convincing trend could be found.…”

Section: Abundance Differences Versus Condensation Temperaturesmentioning

confidence: 99%

“…Meléndez et al (2009) also concluded that solar twins without close-in giant planets chemically resemble the Sun, suggesting that the presence of such planets might prevent the formation of Earth-sized planets. Of course, all these (and more) mechanisms might be at work, rendering the discernment of their relative roles a rather complex undertaking (see, e.g., González Hernández et al 2013;Adibekyan et al 2014;Maldonado et al 2015).…”

Section: Introductionmentioning

confidence: 99%

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The GAPS programme with HARPS-N at TNG

Biazzo

Gratton

Desidera

et al. 2015

A&A

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Binary stars hosting exoplanets are a unique laboratory where chemical tagging can be performed to measure the elemental abundances of both stellar components with high accuracy, with the aim to investigate the formation of planets and their subsequent evolution. Here, we present a high-precision differential abundance analysis of the XO-2 wide stellar binary based on high-resolution HARPS-N at TNG spectra. Both components are very similar K-dwarfs and host planets. Since they formed presumably within the same molecular cloud, we expect that they possess the same initial elemental abundances. We investigated whether planets can cause some chemical imprints in the stellar atmospheric abundances. We measure abundances of 25 elements for both stars with a range of condensation temperature T C = 40−1741 K, achieving typical precisions of ∼0.07 dex. The northern component shows abundances in all elements higher by +0.067 ± 0.032 dex on average, with a mean difference of +0.078 dex for elements with T C > 800 K. The significance of the XO-2N abundance difference relative to XO-2S is at the 2σ level for almost all elements. We discuss that this result might be interpreted as the signature of the ingestion of material by XO-2N or depletion in XO-2S that is due to locking of heavy elements by the planetary companions. We estimate a mass of several tens of M ⊕ in heavy elements. The difference in abundances between XO-2N and XO-2S shows a positive correlation with the condensation temperatures of the elements, with a slope of (4.7 ± 0.9) × 10 −5 dex K −1 , which could mean that both components have not formed terrestrial planets, but first experienced the accretion of rocky core interior to the subsequent giant planets.

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Section: Origin Of the Elemental Abundances Differencementioning

confidence: 73%

Section: Abundance Differences Versus Condensation Temperaturesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The GAPS programme with HARPS-N at TNG

Biazzo

Gratton

Desidera

et al. 2015

A&A

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“…This idea is supported by models of planet formation and evolution based on the core-accretion process (e.g. Ida & Lin 2004;Mordasini et al 2012) Later abundance studies on stars with and without planets confirmed the primordial cloud as the most likely reason for the metal-rich nature of planet-host stars (Santos et al , 2005, although this correlation is valid for giant planet hosts only (Sousa et al 2008(Sousa et al , 2011bBuchhave et al 2012) Interestingly, recent studies suggest that specific element abundances may have a particularly relevant role in the planet formation process (Adibekyan et al 2014 or in its composition . The abundances of volatiles (such as C, N, and O) may be particularly relevant in this respect.…”

Section: Introductionmentioning

confidence: 87%

CNO behaviour in planet-harbouring stars

Suárez-Andrés

Israelian

Hernández

et al. 2016

A&A

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Context. Carbon, nitrogen, and oxygen (CNO) are key elements in stellar formation and evolution, and their abundances should also have a significant impact on planetary formation and evolution. Aims. We present a detailed spectroscopic analysis of 74 solar-type stars, 42 of which are known to harbour planets. We determine the nitrogen abundances of these stars and investigate a possible connection between N and the presence of planetary companions. Methods. We used VLT/UVES to obtain high-resolution near-UV spectra of our targets. Spectral synthesis of the NH band at 3360 Å was performed with the spectral synthesis codes MOOG and FITTING. Results. We identify several spectral windows from which accurate N abundance can be obtained. Nitrogen distributions for stars with and without planets show that planet hosts are nitrogen-rich when compared to single stars. However, given the linear trend between [N/Fe] vs. [Fe/H], this fact can be explained as being due to the metal-rich nature of planet hosts. Conclusions. We conclude that reliable N abundances can be derived for metal-rich solar type stars from the near UV molecular band at 3360 Å. We confirm a linear trend between [N/Fe] and metallicity expected from standard models of Galactic chemical evolution.

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“…The works of Meléndez et al (2009) and Ramírez et al (2009) have triggered several papers investigating relations between [X/Fe]-T C slopes and the existence of planets around stars (Gonzalez et al 2010;González Hernández et al 2010, 2013Schuler et al 2011;Adibekyan et al 2014;Maldonado et al 2015). The results obtained are not very conclusive, partly because the stars included span wider ranges in T eff , log g, and [Fe/H] than the solar twins in Meléndez et al (2009) making the abundance ratios less precise and introducing a dependence of the derived [X/Fe]-T C slopes on possible corrections for Galactic evolution effects.…”

Section: Introductionmentioning

confidence: 99%

High-precision abundances of elements in solar twin stars

Nissen

2015

A&A

240

300

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Context. High-precision determinations of abundances of elements in the atmospheres of the Sun and solar twin stars indicate that the Sun has an unusually low ratio between refractory and volatile elements. This has led to the suggestion that the relation between abundance ratios, [X/Fe], and elemental condensation temperature, T C , can be used as a signature of the existence of terrestrial planets around a star. Aims. HARPS spectra with S /N 600 for 21 solar twin stars in the solar neighborhood and the Sun (observed via reflected light from asteroids) are used to determine very precise (σ ∼ 0.01 dex) differential abundances of elements in order to see how well [X/Fe] is correlated with T C and other parameters such as stellar age. Methods. Abundances of C, O, Na, Mg, Al, Si, S, Ca, Ti, Cr, Fe, Ni, Zn, and Y are derived from equivalent widths of weak and medium-strong spectral lines using MARCS model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Non-LTE effects are considered and taken into account for some of the elements. In addition, precise (σ 0.8 Gyr) stellar ages are obtained by interpolating between Yonsei-Yale isochrones in the log g -T eff diagram. Results. It is confirmed that the ratio between refractory and volatile elements is lower in the Sun than in most of the solar twins (only one star has the same [X/Fe]-T C distribution as the Sun), but for many stars, the relation between [X/Fe] and T C is not well defined.

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On the origin of stars with and without planets

Cited by 95 publications

References 45 publications

The GAPS programme with HARPS-N at TNG

The GAPS programme with HARPS-N at TNG

CNO behaviour in planet-harbouring stars

High-precision abundances of elements in solar twin stars

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