Stellar Pollution in the Solar Neighborhood

Murray, Norman; Chaboyer, Brian; Arras, Phil; Hansen, Brad M. S.; Noyes, R. W.

doi:10.1086/321527

Cited by 106 publications

(138 citation statements)

References 60 publications

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“…Using the code, we derive this quantity as a function of overall stellar mass, as shown at age log t ¼ 5 (because of the code time step, we cannot produce the zero-age convection zone) in Figure 1. Ignoring additional mixing evident in the lithium dip, this is consistent with the results of Murray et al (2001).…”

Section: Implementation Of the Pollution Scenariosupporting

confidence: 89%

Stellar Evolution with Enriched Surface Convection Zones. I. General Effects of Planet Consumption

Cody¹,

Sasselov²

2005

ApJ

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Abundance analyses of stars with planets have revealed that their metallicities are enhanced relative to field stars. Such a trend was originally thought to be due to the accretion of iron-rich planetary material. Based on this assumption, we have developed a stellar evolution code to model stars with nonuniform metallicity distributions. We have calculated polluted stellar evolution tracks for stars with M ¼ 0:9 1:2 M . Our models encompass a range of initial metal content Z ¼ 0:01 0:03, and include metallicity enhancements within the stellar convection zone corresponding to Á Z ¼ 0:005 0:03. We find that the primary effects of metal enhancement on stellar structure and evolution are expansion of the convection zone and downward shift of effective temperature. In addition, we have computed the surface metallicities expected for stars of different mass for fixed quantities of pollution; there appears to be no correlation with present observational data on the metallicities of stars known to harbor planets.

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Section: Implementation Of the Pollution Scenariosupporting

confidence: 89%

Stellar Evolution with Enriched Surface Convection Zones. I. General Effects of Planet Consumption

Cody¹,

Sasselov²

2005

ApJ

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“…In this case, the presence of planets is expected to positively correlate with metallicity. A similar effect is thought to be in action in the solar system (Murray et al 2001), where the total mass of rocky material accreted by the Sun after the shrinking of its convective zone (∼0.4 M ⊕ ) might be too low to cause an appreciable variation of its chemical composition, however. Alternatively, the formation of planetary cores may prevent rocky planetary material to be accreted by the star ).…”

Section: Introductionmentioning

confidence: 95%

“…We estimated how many heavy elements were being accreted or depleted in one of the components following the prescriptions of Murray et al (2001), as in Desidera et al (2004Desidera et al ( , 2006 Table 2, the difference of iron within the convective zone is ∼10 M ⊕ . Assuming to first order a similar composition of meteoritic material, this corresponds to 50 M ⊕ of heavy elements.…”

Section: Origin Of the Elemental Abundances Differencementioning

confidence: 99%

“…While accretion of planetary material may cause huge effects in white dwarfs (e.g., Zuckerman et al 2003), variations of surface abundances are not expected to be large in FGK mainsequence stars due to the dilution of the material within the outer convective envelope (Murray et al 2001). In general, the most prominent effect is probably an over-or underabundance of elements as a function of the grain condensation temperature (T C ), which is different for different elements (Smith et al 2001).…”

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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“…The disks obtained span a mass range going from about 0.008 M to about 0.07 M . Following Murray et al (2001), we relate the dust to gas ratio f dg to the metallicity F e/H of the disk (it is assumed that initially the star and the disk have the same composition) by the relation F e/H = log(f dg /f dg ), where f dg = 0.0167 is the dust to gas ratio corresponding to solar composition. We vary f dg from 0.00667 to 0.0333 using the metallicity distribution of stars in the solar neighborhood (Nordström et al 2004) to define the probability of occurrence of a given disk.…”

Section: Initial Conditionsmentioning

confidence: 99%

Exoplanets: The tip of the iceberg?

et al. 2005

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Abstract. As the number of large scale ground-and space-bound planet detection and imaging projects is growing, the need for theoretical guidance in order to optimize instrumental design is rapidly mounting. In an effort to provide this required framework, we present the results of Monte Carlo simulations of the formation of giant planets and compare them with the current population of exoplanets. Our models show that due to the severe current observational detection bias only a small percentage (3.6 %) of the potentially existing planets can be detected. Indeed, a large number of planetary embryos never grow enough to become giant planets giving raise to a large populations of bodies with masses smaller than 5 M jup . In addition, this observational bias, coupled with the fact that systems enriched in heavy elements tend to form more massive planets, explains the currently observed correlation between stellar metallicity and likelihood to host planets. Finally, we show that the disk gas delivery rate during the late stages of formation actually determines the maximum planetary mass.

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Stellar Pollution in the Solar Neighborhood

Cited by 106 publications

References 60 publications

Stellar Evolution with Enriched Surface Convection Zones. I. General Effects of Planet Consumption

Stellar Evolution with Enriched Surface Convection Zones. I. General Effects of Planet Consumption

The GAPS programme with HARPS-N at TNG

Exoplanets: The tip of the iceberg?

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