New and updated stellar parameters for 90 transit hosts

Mortier, A.; Santos, N. C.; Sousa, S. G.; Fernandes, J.; Adibekyan, V.; Delgado-Mena, E.; Montalto, M.; Israelian, G.

doi:10.1051/0004-6361/201322240

Cited by 100 publications

(128 citation statements)

References 83 publications

(50 reference statements)

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“…These computations are based on equivalent widths of iron lines. Unlike other works, the computations based on specific line list of Sousa et al (2008) show little dependence between surface gravities and effective temperature (Mortier et al 2013b). A similar behaviour was also shown in the paper from Torres et al (2012) for a similar procedure also based on equivalent widths.…”

Section: O B S E Rvat I O Na L Data a N D M E T H O D O L O G Ysupporting

confidence: 81%

“…This analysis only evaluates the individual impact that these parameters have on the mass determination. Correlations between the effective temperature and surface gravity uncertainties were disregarded since the computations based on the specific line list of Sousa et al (2008) show little dependence on surface gravities and effective temperature (Mortier et al 2013b). In this way, we observed that the fraction of stars in the sample which suffer a significant mass shift when this procedure is applied is largest for the spectroscopic approach.…”

Section: R E S U Lt S a N D Discussionmentioning

confidence: 99%

“…In the particular case of using a spectroscopic surface gravity, one obtains what is known as the spectroscopic mass. Mortier et al (2013b) discuss the impact that different methods of surface gravity estimation can have on the determination of stellar masses. In a similar way, Huber et al (2012) compare asteroseismic surface gravities with those obtained from the analysis of photometric light curves.…”

Section: O B S E Rvat I O Na L Data a N D M E T H O D O L O G Ymentioning

confidence: 99%

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On the mass estimation for FGK stars: comparison of several methods

Pinheiro

Fernandes

Cunha

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Stellar evolutionary models simulate well binary stars when individual stellar mass and system metallicity are known. The mass can be derived directly from observations only in the case of multiple stellar systems, mainly binaries. Yet, the number of such stars for which accurate stellar masses are available is rather small. The main goal of this project is to provide realistic mass estimates for a homogeneous sample of about a thousand FGK single stars, using four different methods and techniques. We present the masses inferred according to each one of these methods as well as a final mass estimate consisting in the median of the four mass estimates. The procedures evaluated here include the use of stellar evolutionary models, massluminosity relation and surface gravity spectroscopic observations. By combining the results obtained with different methods, we determine the best mass value for each individual star, as well as the associated error budget. Our results confirm the expected consistency between the different mass estimation methods. None the less, for masses above 1.2 M , the spectroscopic surface gravities seem to overestimate the mass. This result may be a consequence of the spectroscopic surface gravities used in this analysis. Nevertheless, this problem is minimized by the fact that we have several approaches available for deriving stellar masses. Moreover, we suggest an empirical procedure to overcome this issue.

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Section: O B S E Rvat I O Na L Data a N D M E T H O D O L O G Ysupporting

confidence: 81%

Section: R E S U Lt S a N D Discussionmentioning

confidence: 99%

Section: O B S E Rvat I O Na L Data a N D M E T H O D O L O G Ymentioning

confidence: 99%

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On the mass estimation for FGK stars: comparison of several methods

Pinheiro

Fernandes

Cunha

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…The stellar atmospheric parameters were taken from Sousa et al (2008Sousa et al ( , 2011a for HARPS stars and from Santos et al (2004Santos et al ( , 2005, Sousa et al (2006) and Mortier et al (2013) for the rest of the planet hosts. The errors of the parameters from Santos et al (2004Santos et al ( , 2005 are of the order of 44 K for T eff , 0.11 dex for log g, 0.08 km s −1 for ξ t , 0.06 dex for metallicity and 0.05 M for the masses.…”

Section: Discussionmentioning

confidence: 99%

Li depletion in solar analogues with exoplanets

Delgado-Mena

Israelian

Hernández

et al. 2014

A&A

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104

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Aims. We want to study the effects of the formation of planets and planetary systems on the atmospheric Li abundance of planet host stars. Methods. In this work we present new determinations of lithium abundances for 326 main sequence stars with and without planets in the T eff range 5600-5900 K. The 277 stars come from the HARPS sample, the remaining targets were observed with a variety of high-resolution spectrographs. Results. We confirm significant differences in the Li distribution of solar twins (T eff = T ± 80 K, log g = log g ± 0.2 and [Fe/H] = [Fe/H] ± 0.2): the full sample of planet host stars (22) shows Li average values lower than "single" stars with no detected planets (60). If we focus on subsamples with narrower ranges in metallicity and age, we observe indications of a similar result though it is not so clear for some of the subsamples. Furthermore, we compare the observed spectra of several couples of stars with very similar parameters that show differences in Li abundances up to 1.6 dex. Therefore we show that neither age, mass, nor metallicity of a parent star is the only cause for enhanced Li depletion in solar analogues. Conclusions. We conclude that another variable must account for that difference and suggest that this could be the presence of planets that causes additional rotationally induced mixing in the external layers of planet host stars. Moreover, we find indications that the amount of depletion of Li in planet-host solar-type stars is higher when the planets are more massive than Jupiter.

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“…We therefore do not expect surface gravity to introduce significant effects on the computation of individual chemical abundances from non-ionised species. In this line, Mortier et al (2013) computed chemical abundances of 90 stars with transiting exoplanets using spectroscopic log g values and log g estimates derived using the stellar density determined from the light curve. They found that only the abundances from ionised species are significantly affected.…”

Section: Photometric Parameters and Comparison With Previous Workmentioning

confidence: 99%

Searching for signatures of planet formation in stars with circumstellar debris discs

Maldonado

Eiroa

Villaver

et al. 2015

A&A

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Context. Tentative correlations between the presence of dusty circumstellar debris discs and low-mass planets have recently been presented. In parallel, detailed chemical abundance studies have reported different trends between samples of planet and non-planet hosts. Whether these chemical differences are indeed related to the presence of planets is still strongly debated. Aims. We aim to test whether solar-type stars with debris discs show any chemical peculiarity that could be related to the planet formation process. Methods. We determine in a homogeneous way the metallicity, [Fe/H], and abundances of individual elements of a sample of 251 stars including stars with known debris discs, stars harbouring simultaneously debris discs and planets, stars hosting exclusively planets, and a comparison sample of stars without known discs or planets. High-resolution échelle spectra (R ∼ 57 000) from 2−3 m class telescopes are used. Our methodology includes the calculation of the fundamental stellar parameters (T eff , log g, microturbulent velocity, and metallicity) by applying the iron ionisation and equilibrium conditions to several isolated Fe i and Fe ii lines, as well as individual abundances of C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn. Results. No significant differences have been found in metallicity, individual abundances or abundance-condensation temperature trends between stars with debris discs and stars with neither debris nor planets. Stars with debris discs and planets have the same metallicity behaviour as stars hosting planets, and they also show a similar [X/Fe] −T C trend. Different behaviour in the [X/Fe] −T C trends is found between the samples of stars without planets and the samples of planet hosts. In particular, when considering only refractory elements, negative slopes are shown in cool giant planet hosts, whilst positive ones are shown in stars hosting low-mass planets. The statistical significance of the derived slopes is low, however, probably because of the wide range of stellar parameters of our samples. Stars hosting exclusively close-in giant planets behave in a different way, showing higher metallicities and positive [X/Fe] −T C slope. A search for correlations between the [X/Fe] −T C slopes and the stellar properties reveals a moderate but significant correlation with the stellar radius and a weak correlation with the stellar age, which remain even if Galactic chemical evolution effects are considered. No correlation between the [X/Fe] −T C slopes and the disc/planet properties are found. Conclusions. The fact that stars with debris discs and stars with low-mass planets do not show either metal enhancement or a different [X/Fe] −T C trend might indicate a correlation between the presence of debris discs and the presence of low-mass planets. We extend results from previous works based mainly on solar analogues with reported differences in the [X/Fe] −T C trends between planet hosts and non-hosts to a wider range of parameters. However, these differences ...

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New and updated stellar parameters for 90 transit hosts

Cited by 100 publications

References 83 publications

On the mass estimation for FGK stars: comparison of several methods

On the mass estimation for FGK stars: comparison of several methods

Li depletion in solar analogues with exoplanets

Searching for signatures of planet formation in stars with circumstellar debris discs

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