Photospheric Abundances of Volatile and Refractory Elements in Planet-Harboring Stars

Takeda, Yoichi; Sato, Bun’ei; Kambe, Eiji; Aoki, Wako; Honda, Satoshi; Kawanomoto, Satoshi; Masuda, Seiji; Izumiura, Hideyuki; Watanabe, E.; Koyano, Hisashi; Maehara, H.; Norimoto, Yuji; Okada, Takafumi; Shimizu, Yasuhiro; Uraguchi, Fumihiro; Yanagisawa, K.; Yoshida, Michitoshi; Miyama, Shoken M.; Ando, Hiroyasu

doi:10.1093/pasj/53.6.1211

Cited by 81 publications

(65 citation statements)

References 21 publications

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“…Nevertheless, Smith et al (2001) found, using a collection of abundance data from the literature, that about six stars exhibit positive slopes. Other authors (Gonzalez 2006a,b;Sadakane et al 2002;Takeda et al 2001) found no dependence of the abundances on T C .…”

Section: The Link Between Migration and Stellar Abundancesmentioning

confidence: 85%

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Chavero

Reza

Domingos³

et al. 2010

A&A

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The relative distribution of abundances of refractory, intermediate, and volatile elements in stars with planets can be an important tool for investigating the internal migration of a giant planet. This migration can lead to the accretion of planetesimals and the selective enrichment of the star with these elements. We report on a spectroscopic determination of the atmospheric parameters and chemical abundances of the parent stars in transiting planets . Adding data for CoRoT-3 and CoRoT-5 from the literature, we find a flat distribution of the relative abundances as a function of their condensation temperatures. For CoRoT-2, the relatively high lithium abundance and intensity of its Li i resonance line permit us to propose an age of 120 Myr, making this star one of the youngest stars with planets to date. We introduce a new methodology to investigate a relation between the abundances of these stars and the internal migration of their planets. By simulating the internal migration of a planet in a disk formed only by planetesimals, we are able, for the first time, to separate the stellar fractions of refractory, intermediate, and volatile rich planetesimals accreting onto the central star. Intermediate and volatile element fractions enriching the star are similar and much larger than those of pure refractory ones. This result is opposite to what has been considered in the literature for the accreting self-enrichment processes of stars with planets. We also show that these results are highly dependent on the model adopted for the disk distribution regions in terms of refractory, intermediate, and also volatile elements and other parameters considered. We note however, that this self-enrichment mechanism is only efficient during the first 20-30 Myr or later in the lifetime of the disk when the surface convection layers of the central star for the first time attain its minimum size configuration.

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Section: The Link Between Migration and Stellar Abundancesmentioning

confidence: 85%

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Chavero

Reza

Domingos³

et al. 2010

A&A

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“…Previous studies (e.g., Smith et al 2001;Takeda et al 2001;Santos et al 2004;Ecuvillon et al 2006;Gonzalez & Laws 2007) have been cautious about reaching strong conclusions based on abundance trends with T C because of the still relatively large systematic errors associated with their analyses in comparison with the small size of the effect. To detect this trend, a precision of 0.03 dex or better is required.…”

Section: Planetary Signatures In the Abundance Trends?mentioning

confidence: 99%

Accurate abundance patterns of solar twins and analogs

Ramírez¹,

Meléndez

Asplund³

2009

A&A

276

369

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We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution (R 60 000), high signalto-noise ratio (S /N 200) spectra. The estimated errors in the elemental abundances relative to solar are as small as 0.025 dex. The abundance ratios [X/Fe] as a function of [Fe/H] agree closely with previously established patterns of Galactic thin-disk chemical evolution. Interestingly, the majority of our stars show a significant correlation between [X/Fe] and condensation temperature (T C ). In the sample of 22 stars with parameters closest to solar, we find that, on average, low T C elements are depleted with respect to high T C elements in the solar twins relative to the Sun by about 0.08 dex ( 20%). An increasing trend is observed for the abundances as a function of T C for 900 < T C < 1800 K, while abundances of lower T C elements appear to be roughly constant. We speculate that this is a signature of the planet formation that occurred around the Sun but not in the majority of solar twins. If this hypothesis is correct, stars with planetary systems like ours, although rare (frequency of 15%), may be identified through a very detailed inspection of the chemical compositions of their host stars.

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“…It may be worthwhile, from another point of view, to check the consistency of this treatment on nearby solar-type stars, which have been recently analyzed by Takeda et al (2001) to study the abundance characteristics of planet-harboring stars. Figure 12 shows the comparison of the non-LTE abundance of O  7771-5 triplet (with the NLTE correction obtained by using the formula described in this study) with the LTE abundance of O  6158.2 (a) and [O ] 6300.3 (b), which were derived from either equivalent-widths or spectrum-synthesis technique (with the same line data as given in Table 1) as described in Takeda et al (2001).…”

Section: Appendix A: On the Effect And Treatment Of H I Collisionmentioning

confidence: 99%

“…Figure 12 shows the comparison of the non-LTE abundance of O  7771-5 triplet (with the NLTE correction obtained by using the formula described in this study) with the LTE abundance of O  6158.2 (a) and [O ] 6300.3 (b), which were derived from either equivalent-widths or spectrum-synthesis technique (with the same line data as given in Table 1) as described in Takeda et al (2001). Note that LTE can be safely applied to these latter two lines (cf.…”

Section: Appendix A: On the Effect And Treatment Of H I Collisionmentioning

confidence: 99%

Oxygen line formation in late-F through early-K disk/halo stars

Takeda

2003

A&A

156

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Abstract. In order to investigate the formation of O  7771-5 and [O ] 6300/6363 lines, extensive non-LTE calculations for neutral atomic oxygen were carried out for wide ranges of model atmosphere parameters, which are applicable to early-K through late-F halo/disk stars of various evolutionary stages. The formation of the triplet O  lines was found to be well described by the classical two-level-atom scattering model, and the non-LTE correction is practically determined by the parameters of the line-transition itself without any significant relevance to the details of the oxygen atomic model. This simplifies the problem in the sense that the non-LTE abundance correction is essentially determined only by the line-strength (W λ ), if the atmospheric parameters of T eff , log g, and ξ are given, without any explicit dependence of the metallicity; thus allowing a useful analytical formula with tabulated numerical coefficients. On the other hand, our calculations lead to the robust conclusion that LTE is totally valid for the forbidden An inspection of the parameter-dependence of this discordance indicates that the extent of the discrepancy tends to be comparatively lessened for higher T eff / log g stars, suggesting the preference of dwarf (or subgiant) stars for studying the oxygen abundances of metal-poor stars.

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Photospheric Abundances of Volatile and Refractory Elements in Planet-Harboring Stars

Cited by 81 publications

References 21 publications

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Accurate abundance patterns of solar twins and analogs

Oxygen line formation in late-F through early-K disk/halo stars

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