Statistical Equilibrium of Copper in the Solar Atmosphere

Shi, Jianrong; Gehren, T.; Zeng, Jiaolong; Mashonkina, L.; Zhao, Gang

doi:10.1088/0004-637x/782/2/80

Cited by 30 publications

(69 citation statements)

References 27 publications

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“…Our Cu abundances in 3D and with HM are not too different from the results of Shi et al (2014;4.19 ± 0.10, from ten lines), Kock & Richter (1968;4.16±0.08, from six lines) and Sneden & Crocker (1988;4.12, from two lines). We do not reproduce the rather large difference in abundance found by Shi et al (2014) between the low and high excitation lines with the HM model. However, our sample only includes one of the low excitation lines used by those authors.…”

Section: Coppercontrasting

confidence: 73%

“…NLTE Cu  line formation in the Sun was investigated by Shi et al (2014), who found positive NLTE corrections (≈+0.02 dex) for our first three lines, and a larger negative correction (≈−0.05 dex) for the last line (Cu  809.3 nm). We adopt their results for S H = 0.1, as recommended in their paper.…”

Section: Coppersupporting

confidence: 54%

“…Interestingly, accounting for departures from LTE as computed by Shi et al (2014) slightly increases the line-to-line scatter (σ = 0.03 and 0.05 dex, respectively) but the net effect on the Cu abundance is small (−0.01 dex). Our Cu abundances in 3D and with HM are not too different from the results of Shi et al (2014;4.19 ± 0.10, from ten lines), Kock & Richter (1968;4.16±0.08, from six lines) and Sneden & Crocker (1988;4.12, from two lines). We do not reproduce the rather large difference in abundance found by Shi et al (2014) between the low and high excitation lines with the HM model.…”

Section: Coppermentioning

confidence: 99%

“…Because the Cu  793.3 nm and Cu  809.3 nm lines differ only in the J values of their lower levels, and Shi et al (2014) explain the large negative NLTE offset in the abundance returned by Cu  809.3 nm as mainly due to underpopulation of the upper level of this transition, we assume that the NLTE correction for Cu  793.3 nm is the same as for Cu  809.3 nm. The addition of NLTE corrections for Cu  is a new feature of the analysis here, compared to AGSS09.…”

Section: Coppermentioning

confidence: 99%

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The elemental composition of the Sun

Grevesse

Scott

Asplund

et al. 2014

A&A

210

252

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We re-evaluate the abundances of the elements in the Sun from copper (Z = 29) to thorium (Z = 90). Our results are mostly based on neutral and singly-ionised lines in the solar spectrum. We use the latest 3D hydrodynamic solar model atmosphere, and in a few cases also correct for departures from local thermodynamic equilibrium (LTE) using non-LTE (NLTE) calculations performed in 1D. In order to minimise statistical and systematic uncertainties, we make stringent line selections, employ the highest-quality observational data and carefully assess oscillator strengths, hyperfine constants and isotopic separations available in the literature, for every line included in our analysis. Our results are typically in good agreement with the abundances in the most pristine meteorites, but there are some interesting exceptions. This analysis constitutes both a full exposition and a slight update of the relevant parts of the preliminary results we presented in Asplund et al. (2009, ARA&A, 47, 481), including full line lists and details of all input data that we have employed.

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Section: Coppercontrasting

confidence: 73%

Section: Coppersupporting

confidence: 54%

Section: Coppermentioning

confidence: 99%

Section: Coppermentioning

confidence: 99%

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The elemental composition of the Sun

Grevesse

Scott

Asplund

et al. 2014

A&A

210

252

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“…A revised version of the DETAIL program (Butler & Giddings 1985) figure) as a function of continuum optical depth at 5000 Å for the model atmosphere of G05-40. The collision with neutral hydrogen was scaled by a factor of 0.1 following Shi et al (2014). accelerated lambda iteration was employed to carry out the calculations.…”

Section: Non-lte Calculationsmentioning

confidence: 99%

Non-LTE analysis of copper abundances for the two distinct halo populations in the solar neighborhood

Yan

Shi

Nissen

et al. 2015

A&A

Self Cite

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Context. Two distinct halo populations were found in the solar neighborhood by a series of works. They can be clearly separated by [α/Fe] and several other elemental abundance ratios including [Cu/Fe]. Very recently, a non-local thermodynamic equilibrium (non-LTE) study revealed that relatively large departures exist between LTE and non-LTE results in copper abundance analysis. The study also showed that non-LTE effects of neutral copper vary with stellar parameters and thus affect the [Cu/Fe] trend. Aims. We aim to derive the copper abundances for the stars from the sample of Nissen & Schuster (2010) with both LTE and non-LTE calculations. Based on our results, we study the non-LTE effects of copper and investigate whether the high-α population can still be distinguished from the low-α population in the non-LTE [Cu/Fe] results. Methods. Our differential abundance ratios are derived from the high-resolution spectra collected from VLT/UVES and NOT/FIES spectrographs. Applying the MAFAGS opacity sampling atmospheric models and spectrum synthesis method, we derive the non-LTE copper abundances based on the new atomic model with current atomic data obtained from both laboratory and theoretical calculations. Conclusions. The non-LTE effects are strong for copper, especially in metal-poor stars. Our results confirmed that there are two distinct halo populations in the solar neighborhood. The dichotomy in copper abundance is a peculiar feature of each population, suggesting that they formed in different environments and evolved obeying diverse scenarios.

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The Solar Twin Planet Search

Meléndez

Bedell

Bean

et al. 2016

A&A

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Context. More than two thousand exoplanets have been discovered to date. Of these, only a small fraction have been detected around solar twins, which are key stars because we can obtain accurate elemental abundances especially for them, which is crucial for studying the planet-star chemical connection with the highest precision. Aims. We aim to use solar twins to characterise the relationship between planet architecture and stellar chemical composition. Methods. We obtained high-precision (1 m s −1 ) radial velocities with the HARPS spectrograph on the ESO 3.6 m telescope at La Silla Observatory and determined precise stellar elemental abundances (∼0.01 dex) using spectra obtained with the MIKE spectrograph on the Magellan 6.5 m telescope. Results. Our data indicate the presence of a planet with a minimum mass of 26 ± 4 Earth masses around the solar twin HIP 68468. The planet is more massive than Neptune (17 Earth masses), but unlike the distant Neptune in our solar system (30 AU), HIP 68468c is close-in, with a semi-major axis of 0.66 AU, similar to that of Venus. The data also suggest the presence of a super-Earth with a minimum mass of 2.9 ± 0.8 Earth masses at 0.03 AU; if the planet is confirmed, it will be the fifth least massive radial velocity planet candidate discovery to date and the first super-Earth around a solar twin. Both isochrones (5.9 ± 0.4 Gyr) and the abundance ratio [Y/Mg] (6.4 ± 0.8 Gyr) indicate an age of about 6 billion years. The star is enhanced in refractory elements when compared to the Sun, and the refractory enrichment is even stronger after corrections for Galactic chemical evolution. We determined a nonlocal thermodynamic equilibrium Li abundance of 1.52 ± 0.03 dex, which is four times higher than what would be expected for the age of HIP 68468. The older age is also supported by the low log (R HK ) (-5.05) and low jitter (<1 m s −1 ). Engulfment of a rocky planet of 6 Earth masses can explain the enhancement in both lithium and the refractory elements. Conclusions. The super-Neptune planet candidate is too massive for in situ formation, and therefore its current location is most likely the result of planet migration that could also have driven other planets towards its host star, enhancing thus the abundance of lithium and refractory elements in HIP 68468. The intriguing evidence of planet accretion warrants further observations to verify the existence of the planets that are indicated by our data and to better constrain the nature of the planetary system around this unique star.

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Statistical Equilibrium of Copper in the Solar Atmosphere

Cited by 30 publications

References 27 publications

The elemental composition of the Sun

The elemental composition of the Sun

Non-LTE analysis of copper abundances for the two distinct halo populations in the solar neighborhood

The Solar Twin Planet Search

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