Spectrometric composition of nearby K dwarfs

Kotoneva, Eira; Shi, Jianrong; Zhao, Gang; Liu, Y. J.

doi:10.1051/0004-6361:20042498

Cited by 7 publications

(16 citation statements)

References 10 publications

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“…The photometric determinations include three different approaches. Gratton et al (2000) used theoretical calibrations for B − V and b − y colour indices, while Kotoneva et al (2006) applied an empirical calibration of R − I colour indices based on spectroscopic temperatures for GK dwarfs. The determinations by González Hernández & Bonifacio (2009) and Casagrande et al (2011) are both based on the IRFM with 2MASS colour indices.…”

Section: The Metal-poor K Dwarf Gmb 1830mentioning

confidence: 99%

GaiaFGK benchmark stars: Effective temperatures and surface gravities

Heiter

Jofré

Gustafsson

et al. 2015

A&A

287

414

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Context. In the era of large Galactic stellar surveys, carefully calibrating and validating the data sets has become an important and integral part of the data analysis. Moreover, new generations of stellar atmosphere models and spectral line formation computations need to be subjected to benchmark tests to assess any progress in predicting stellar properties. Aims. We focus on cool stars and aim at establishing a sample of 34 Gaia FGK benchmark stars with a range of different metallicities. The goal was to determine the effective temperature and the surface gravity independently of spectroscopy and atmospheric models as far as possible. Most of the selected stars have been subjected to frequent spectroscopic investigations in the past, and almost all of them have previously been used as reference, calibration, or test objects. Methods. Fundamental determinations of T eff and log g were obtained in a systematic way from a compilation of angular diameter measurements and bolometric fluxes and from a homogeneous mass determination based on stellar evolution models. The derived parameters were compared to recent spectroscopic and photometric determinations and to gravity estimates based on seismic data. Results. Most of the adopted diameter measurements have formal uncertainties around 1%, which translate into uncertainties in effective temperature of 0.5%. The measurements of bolometric flux seem to be accurate to 5% or better, which contributes about 1% or less to the uncertainties in effective temperature. The comparisons of parameter determinations with the literature in general show good agreements with a few exceptions, most notably for the coolest stars and for metal-poor stars. Conclusions. The sample consists of 29 FGK-type stars and 5 M giants. Among the FGK stars, 21 have reliable parameters suitable for testing, validation, or calibration purposes. For four stars, future adjustments of the fundamental T eff are required, and for five stars the log g determination needs to be improved. Future extensions of the sample of Gaia FGK benchmark stars are required to fill gaps in parameter space, and we include a list of suggested candidates.

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Section: The Metal-poor K Dwarf Gmb 1830mentioning

confidence: 99%

GaiaFGK benchmark stars: Effective temperatures and surface gravities

Heiter

Jofré

Gustafsson

et al. 2015

A&A

287

414

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“… The determination of the stellar parameters, such as effective temperature, surface gravity and microturbulence, is required. We note that there are large differences in temperatures based on different colour calibrations (see Kotoneva et al 2006 for details). A large discrepancy between Fe i and Fe ii abundances exists, and seems to depend on the effective temperature and surface gravity. There is a large star‐to‐star scatter for the abundances of all individual elements; however, such a scenario has not been confirmed by other studies (Feltzing & Gustafsson 1998; Mishenina et al 2008). …”

Section: Introductionmentioning

confidence: 76%

“…Following the work of Kotoneva et al (2006), our sample of lower‐main‐sequence stars is selected from the European Space Agency (ESA) Hipparcos catalogue (ESA 1997), which satisfies the criterion 5.5 < M V < 7.3. All known multiple systems and suspected binaries were removed (see Kotoneva et al 2006 for details).…”

Section: Observationsmentioning

confidence: 99%

“…Such an attempt was made by Kotoneva et al (2006); however, there are still some problems that need to be investigated, detailed below, which prompt us to proceed with this analysis in order to derive reliable results for a large sample of nearby stars of such type.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Spectroscopic analysis of nearby lower-main-sequence stars

Wang¹,

Shi²,

Zhao³

2009

Monthly Notices of the Royal Astronomical Society

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Abundances of O, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Fe, Ni and Ba are determined for 30 nearby lower‐main‐sequence stars in the Northern sky using high‐resolution, high signal‐to‐noise ratio spectra. Our results show an equilibrium of [Fe/H]I and [Fe/H]II and a much smaller star‐to‐star scatter of the abundance ratios as a function of metallicity compared with the results of Kotoneva et al. The non‐local thermodynamic equilibrium (non‐LTE) corrections for oxygen are considered and found to be small (∼−0.04 dex). A flat trend of [O/Fe] exists over the whole metallicity range. The non‐LTE effects for some important elements are discussed, and it is found that the abundance pattern for our programme stars is very similar to that of F and G dwarfs.

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GaiaFGK benchmark stars: abundances ofαand iron-peak elements

Jofré

Heiter

Soubiran

et al. 2015

A&A

140

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Context. In the current era of large spectroscopic surveys of the Milky Way, reference stars for calibrating astrophysical parameters and chemical abundances are of paramount importance. Aims. We determine elemental abundances of Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni for our predefined set of Gaia FGK benchmark stars. Methods. By analysing high-resolution spectra with a high signal-to-noise ratio taken from several archive datasets, we combined results of eight different methods to determine abundances on a line-by-line basis. We performed a detailed homogeneous analysis of the systematic uncertainties, such as differential versus absolute abundance analysis. We also assessed errors that are due to non-local thermal equilibrium and the stellar parameters in our final abundances. Results. Our results are provided by listing final abundances and the different sources of uncertainties, as well as line-by-line and method-by-method abundances. Conclusions. The atmospheric parameters of the Gaia FGK benchmark stars are already being widely used for calibration of several pipelines that are applied to different surveys. With the added reference abundances of ten elements, this set is very suitable for calibrating the chemical abundances obtained by these pipelines.

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Spectrometric composition of nearby K dwarfs

Cited by 7 publications

References 10 publications

GaiaFGK benchmark stars: Effective temperatures and surface gravities

GaiaFGK benchmark stars: Effective temperatures and surface gravities

Spectroscopic analysis of nearby lower-main-sequence stars

GaiaFGK benchmark stars: abundances ofαand iron-peak elements

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