J/A+A/597/A52 K and G dwarfs stellar granulation variability (Meunier+, 2017)
Variability of stellar granulation and convective blueshift with spectral type and magnetic activity. I. K and G main sequence stars. Meunier N., Lagrange A.-M., Mbemba Kabuiku L., Alex M., Mignon L., Borgniet S. <Astron. Astrophys. 597, A52 (2017)> =2017A&A...597A..52M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Stars, K-type ; Stars, G-type ; Magnetic fields ; Radial velocities Keywords: convection - stars: magnetic field - stars: activity - Sun: granulation - techniques: radial velocities Abstract: In solar-type stars, the attenuation of convective blueshift by stellar magnetic activity dominates the RV (radial velocity) variations over the low amplitude signal induced by low mass planets. Models of stars that differ from the Sun will require a good knowledge of the attenuation of the convective blueshift to estimate its impact on the variations. It is therefore crucial to precisely determine not only the amplitude of the convective blueshift for different types of stars, but also the dependence of this convective blueshift on magnetic activity, as these are key factors in our model producing the RV. We studied a sample of main sequence stars with spectral types from G0 to K2 and focused on their temporally averaged properties: the activity level and a criterion allowing to characterise the amplitude of the convective blueshift. This criterion is derived from the dependence of the convective blueshift with the intensity at the bottom of a large set of selected spectral lines. Description: Table 3 lists stars studied in the paper (HARPS data from the ESO archive), together with informations from various sources and outputs from our analysis. The number of stars is 167. Table 4 lists spectral lines used in the papers. It gives their laboratory wavelength, elements, and number of data sets in which the line is used. The number of lines is 196. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 60 167 Lists of studied stars table4.dat 19 196 List spectral lines used
See also: J/A+A/487/373 : Spectroscopic parameters of 451 HARPS-GTO stars (Sousa+, 2008) Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Star name 12- 13 A2 --- SpType Spectral type from SIMBAD (CDS) 15- 18 F4.2 mag B-V B-V colour index from SIMBAD (CDS) 20- 23 I4 K Teff Effective temperature from Sousa et al. (2008, Cat. J/A+A/487/373) 25- 29 I5 --- Nsp Number of spectra used in the analysis 31- 37 F7.1 --- TSS Slope of the radial velocity versus line intensity (1) 39- 43 F5.1 --- e_TSS 1 σ uncertainty on the TSS 45- 50 F6.3 [-] logR'HK Averaged logR'HK index 52- 56 F5.3 [-] e_logR'HK 1 σ uncertainty logR'HK 58- 60 I3 m/s ConvBL Convective blueshift (2)
Note (1): TSS: Slope of the radial velocity versus line intensity, where the radial velocity and intensity are computed at the bottom of each line, in m/s/(F/Fc) units. F/Fc represent the relative intensity (with the continuuml of the spectra normalized to 1) Note (2): Convective blueshift is derived from the TSS in Section 4.1.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 9 F9.4 0.1nm Lambda Wavelength (1) 13- 16 A4 --- El Element 19 I1 --- NB Number of data sets in which it is used
Note (1): TiI and FeII wavelengths are from Dravins (2008A&A...492..199D), FeI wavelength are from Nave et al. (1994ApJS...94..221N).
Acknowledgements: Nadege Meunier, nadege.meunier(at)univ-grenoble-alpes.fr
(End) Patricia Vannier [CDS] 05-Oct-2016
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