The GAPS programme with HARPS-N at TNG

Biazzo, K.; Gratton, R.; Desidera, S.; Lucatello, S.; Sozzetti, A.; Bonomo, A. S.; Damasso, M.; Gandolfi, D.; Affer, L.; Boccato, C.; Borsa, F.; Claudi, R.; Cosentino, R.; Covino, E.; Knapic, C.; Lanza, A. F.; Maldonado, J.; Marzari, F.; Micela, G.; Molaro, P.; Pagano, I.; Pedani, M.; Pillitteri, I.; Piotto, G.; Poretti, E.; Rainer, M.; Santos, N. C.; Scandariato, G.; Sánchez, R. Zanmar

doi:10.1051/0004-6361/201526375

Cited by 73 publications

(75 citation statements)

References 89 publications

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“…The analysis is based on the line-by-line differential method (e.g., Meléndez et al 2012Meléndez et al , 2014aMonroe et al 2013;Liu et al 2014;Ramírez et al 2014;Biazzo et al 2015;Nissen 2015;Spina et al 2016;Saffe et al 2015). We measured the EWs using the splot task in IRAF, fitting the line profiles using Gaussians.…”

Section: Stellar Parametersmentioning

confidence: 99%

High-precision analysis of the solar twin HIP 100963

Galarza

Meléndez

Ramírez

et al. 2016

A&A

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Context. HIP 100963 was one of the first solar twins identified. Although some high-precision analyses are available, a comprehensive high-precision study of chemical elements from different nucleosynthetic sources is still lacking from which to obtain potential new insights on planets, stellar evolution, and Galactic chemical evolution (GCE). Aims. We analyze and investigate the origin of the abundance pattern of HIP 100963 in detail, in particular the pattern of the light element Li, the volatile and refractory elements, and heavy elements from the s-and r-processes. Methods. We used the HIRES spectrograph on the Keck I telescope to acquire high-resolution (R ≈ 70 000) spectra with a high signal-to-noise ratio (S/N ≈ 400-650 per pixel) of HIP 100963 and the Sun for a differential abundance analysis. We measured the equivalent widths (EWs) of iron lines to determine the stellar parameters by employing the differential spectroscopic equilibrium. We determined the composition of volatile, refractory, and neutron-capture elements through a differential abundance analysis with respect to the Sun. Results. The stellar parameters we found are T eff = 5818 ± 4 K, log g = 4.49 ± 0.01 dex, v t = 1.03 ± 0.01 km s −1 , and [Fe/H] = − 0.003 ± 0.004 dex. These low errors allow us to compute a precise mass (1.03 +0.02−0.01 M ) and age (2.0 ± 0.4 Gyr), obtained using Yonsei-Yale isochrones. Using our [Y/Mg] ratio, we have determined an age of 2.1 ± 0.4 Gyr, in agreement with the age computed using isochrones. Our isochronal age also agrees with the age determined from stellar activity (2.4 ± 0.3 Gyr). We study the abundance pattern with condensation temperature (T cond ) taking corrections by the GCE into account. We show that the enhancements of neutron-capture elements are explained by contributions from both the s-and r-process. The lithium abundance follows the tight Li-age correlation seen in other solar twins. Conclusions. We confirm that HIP 100963 is a solar twin and demonstrate that its abundance pattern is about solar after corrections for GCE. The star also shows enrichment in s-and r-process elements, as well as depletion in lithium that is caused by stellar evolution.

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Section: Stellar Parametersmentioning

confidence: 99%

High-precision analysis of the solar twin HIP 100963

Galarza

Meléndez

Ramírez

et al. 2016

A&A

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“…However, besides the increasing number of recent studies (e.g. Biazzo et al 2015;da Silva et al 2015;Maldonado et al 2015;Nissen 2015;Ramírez et al 2015;Thiabaud et al 2015), the only well established correlation found, so far, is the one that relates the stellar metallicity with the probability of hosting a gas giant planet (e.g. Gonzalez 1997;Santos et al 2004;Fischer & Valenti 2005).…”

Section: Introductionmentioning

confidence: 99%

Evolved stars and the origin of abundance trends in planet hosts

Maldonado

Villaver

2016

A&A

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Context. Detailed chemical abundance studies have revealed different trends between samples of planet and non-planet hosts. Whether these trends are related to the presence of planets or not is strongly debated. At the same time, tentative evidence that the properties of evolved stars with planets may be different from what we know for main-sequence hosts has recently been reported. Aims. We aim to test whether evolved stars with planets show any chemical peculiarity that could be related to the planet formation process. Methods. In a consistent way, we determine the metallicity and individual abundances of a large sample of evolved (subgiants and red giants) and main-sequence stars that are with and without known planetary companions, and discuss their metallicity distribution and trends. Our methodology is based on the analysis of high-resolution échelle spectra (R 57 000) from 2−3 m class telescopes. It includes the calculation of the fundamental stellar parameters, as well as individual abundances of C, O , Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, and Zn. Results. No differences in the [X/Fe] vs. condensation temperature (T C ) slopes are found between the samples of planet and nonplanet hosts when all elements are considered. However, if the analysis is restricted to only refractory elements, differences in the T C -slopes between stars with and without known planets are found. This result is found to be dependent on the stellar evolutionary stage, as it holds for main-sequence and subgiant stars, while there seems to be no difference between planet and non-planet hosts among the sample of giants. A search for correlations between the T C -slope and the stellar properties reveals significant correlations with the stellar mass and the stellar age. The data also suggest that differences in terms of mass and age between main-sequence planet and non-planet hosts may be present. Conclusions. Our results are well explained by radial mixing in the Galaxy. The sample of giants contains stars that are more massive and younger than their main-sequence counterparts. This leads to a sample of stars that are possibly less contaminated by stars that were not born in the solar neighbourhood, leading to no chemical differences between planet and non-planet hosts. The sample of main-sequence stars may contain more stars from the outer disc (specially the non-planet host sample) which might lead to the differences observed in the chemical trends.

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“…Several authors studied the T c trend in binary stars with and without planetary companions (e.g., Liu et al 2014;Saffe et al 2015;Mack et al 2016) or binary stars where both components host planets (e.g., Biazzo et al 2015;Teske et al 2015Teske et al , 2016Ramírez et al 2015). The results and conclusions of these studies show that there are no systematic differences in the chemical abundances of stars with and without planets in binary systems.…”

Section: Introductionmentioning

confidence: 99%

ζ²Reticuli, its debris disk, and its lonely stellar companionζ¹Ret

Adibekyan

Delgado-Mena

Figueira

et al. 2016

A&A

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Context. Several studies have reported a correlation between the chemical abundances of stars and condensation temperature (known as T c trend). Very recently, a strong T c trend was reported for the ζ Reticuli binary system, which consists of two solar analogs. The observed trend in ζ 2 Ret relative to its companion was explained by the presence of a debris disk around ζ 2 Ret. Aims. Our goal is to re-evaluate the presence and variability of the T c trend in the ζ Reticuli system and to understand the impact of the presence of the debris disk on a star. Methods. We used very high-quality spectra of the two stars retrieved from the HARPS archive to derive very precise stellar parameters and chemical abundances. We derived the stellar parameters with the classical (nondifferential) method, while we applied a differential line-by-line analysis to achieve the highest possible precision in abundances, which are fundamental to explore for very tiny differences in the abundances between the stars. Results. We confirm that the abundance difference between ζ 2 Ret and ζ 1 Ret shows a significant (∼2σ) correlation with T c . However, we also find that the T c trends depend on the individual spectrum used (even if always of very high quality). In particular, we find significant but varying differences in the abundances of the same star from different individual high-quality spectra. Conclusions. Our results for the ζ Reticuli system show, for example, that nonphysical factors, such as the quality of spectra employed and errors that are not accounted for, can be at the root of the T c trends for the case of individual spectra.

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The GAPS programme with HARPS-N at TNG

Cited by 73 publications

References 89 publications

High-precision analysis of the solar twin HIP 100963

High-precision analysis of the solar twin HIP 100963

Evolved stars and the origin of abundance trends in planet hosts

ζ²Reticuli, its debris disk, and its lonely stellar companionζ¹Ret

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The GAPS programme with HARPS-N at TNG

Cited by 73 publications

References 89 publications

High-precision analysis of the solar twin HIP 100963

High-precision analysis of the solar twin HIP 100963

Evolved stars and the origin of abundance trends in planet hosts

ζ2Reticuli, its debris disk, and its lonely stellar companionζ1Ret

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ζ²Reticuli, its debris disk, and its lonely stellar companionζ¹Ret