J/A+A/659/A3ivo://CDS.VizieR/J/A+A/659/A3doi:10.26093/cds/vizier.36590003CDSSeli B.Olah K.Kriskovics L.Kovari Zs.Vida K.Balazs L.G.,Laming J.M.van Driel-Gesztelyi L.Baker D.2023-01-30T11:31:53Z2022-12-30T08:35:02ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frpeculiar-variable-starschemical-abundancesvisible-astronomyThe different elemental abundances of the photosphere and the corona are striking features of not only the Sun, but other stars as well. This phenomenon is known as the FIP effect (FIP stands for first ionization potential), and its strength can be characterized by the FIP bias, the logarithmic abundance difference between low- and high-FIP elements in the corona, compared to the photosphere. The FIP bias was shown to depend on the surface temperature of the star. We aim to extend the Teff-FIP bias relationship to a larger stellar sample and analyse the effect of other astrophysical parameters on the relation (e.g., surface gravity, age, activity indicators). Methods: We compiled FIP bias and other parameters for 59 stars for which coronal composition is available, now including evolved stars. Using principal component analysis and linear discriminant analysis, we searched for correlations with other astrophysical parameters within the sample which may influence the stellar FIP bias. Adding stars to the Teff-FIP bias diagram unveiled new features in its structure. In addition to the previously known relationship, there appears to be a second branch, a parallel sequence about 0.5 dex above it. While the Teff remains the main determinant of the FIP bias, other parameters such as stellar activity indicators also have influence. We find three clusters in the FIP bias determinant parameter space. One distinct group is formed by the evolved stars. Two groups contain main sequence stars in continuation separated roughly by the sign change of the FIP-bias value. The new branch of the Teff-FIP bias diagram contains stars with higher activity level, in terms of X-ray flux and rotational velocity. The Rossby number also seems to be important, indicating possible dependence on the type of dynamo operating in these stars influencing their FIP bias. The two main sequence clusters run from the earliest spectral types of A-F with shallow convection zones through G-K-early M stars with gradually deeper convection zones, and end up with the fully convective M dwarf stars, depicting the change of the dynamo type with the internal differences of the main sequence stars in connection with the FIP-bias values.2022A&A...659A...3Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/659/A3CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/659/A3https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/659/A3http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/659/A3https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/659/A3https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/659/A3http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/659/A3GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/659/A3/table2 (Astrophysical parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/659/A3/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/659/A3/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/659/A3/table2?GETtext/xml+votable180.050000true154.9011719.87000280.0055555555555555566/311 845 924 1504 3986 4444 5377 5670 6241 6340 7264 7763 8790 8843 9442 10255 10375 11856 12770 13301 13743 13778 13947 16834 17989 18234 20071 20286 21285 22300 22707 23191 23230 23369 24151 27462 28151 29196 30543 31751 33034 33116 33717 36697 38437 41591 41679 41763 48105 48263 48274https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/659/A3?format=asciiOpticaldefaultJ/A+A/659/A3/table2Astrophysical parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadNameSimbad column added by the CDSmeta.idcharnullableNameName of the starmeta.id;meta.maincharFIPbiaslitLiterature FIP bias (1)arith.factorfloate_FIPbiaslitUncertainty of the literature FIP biasstat.errorfloatFIPbiasKNNKNN FIP biasarith.factorfloate_FIPbiasKNNUncertainty of the KNN FIP biasstat.errorfloatAge? AgeGyrtime.agefloatnullableTeffEffective temperatureKphys.temperature.effectiveinte_TeffUncertainty of the effective temperatureKstat.error;phys.temperature.effectiveintloggSurface gravity in cgs unitslog(cm.s**-2)phys.gravityfloat[Fe/H]? Metallicityphys.abund.ZfloatnullableRadStellar radiussolRadphys.size.radiusfloatProt? Rotational perioddtime.periodfloatnullablevrot? Rotational velocity at the surfacekm/sphys.veloc.rotatfloatnullableRo? Rossby numberstat.paramfloatnullablelogRHK? logRHK chromospheric flux ratiophot.flux;arith.ratiofloatnullablelogLxLogarithm of X-ray luminosity (erg/s)log(1e-07W)phys.luminosity;em.X-rayfloatlogFxLogarithm of X-ray flux (erg/s/cm2)log(mW.m**-2)phot.flux;em.X-rayfloat_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullableJ/A+A/659/A3/tablea1Calculation of the literature FIP bias[N/Fe]cor? Logarithmic coronal N/Fe ratio (G1)phys.abundfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the starmeta.id;meta.mainchar[C/Fe]cor? Logarithmic coronal C/Fe ratio (G1)phys.abundfloatnullable[O/Fe]corLogarithmic coronal O/Fe ratio (G1)phys.abundfloat[Ne/Fe]corLogarithmic coronal Ne/Fe ratio (G1)phys.abundfloat[C/Fe]phot? Logarithmic photospheric C/Fe ratio (G2)phys.abundfloatnullable[N/Fe]phot? Logarithmic photospheric N/Fe ratio (G2)phys.abundfloatnullable[O/Fe]photLogarithmic photospheric O/Fe ratio (G2)phys.abundfloat[Ne/Fe]photLogarithmic photospheric Ne/Fe ratio (G2)phys.abundfloatFIPbiaslitLiterature FIP bias (1)arith.factorfloate_FIPbiaslitUncertainty of the literature FIP biasstat.errorfloatJ/A+A/659/A3/tablea2Calculation of the KNN FIP bias[Ne/Fe]corLogarithmic coronal Ne/Fe ratio (G1)phys.abundfloat[C/Fe]phot? Logarithmic photospheric C/Fe ratio (G2)phys.abundfloatnullable[N/Fe]phot? Logarithmic photospheric N/Fe ratio (G2)phys.abundfloatnullable[O/Fe]photLogarithmic photospheric O/Fe ratio (G2)phys.abundfloat[Ne/Fe]photLogarithmic photospheric Ne/Fe ratio (G2)phys.abundfloatFIPbiasKNNKNN FIP biasarith.factorfloate_FIPbiasKNNUncertainty of the KNN FIP biasstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the starmeta.id;meta.mainchar[C/Fe]cor? Logarithmic coronal C/Fe ratio (G1)phys.abundfloatnullable[N/Fe]cor? Logarithmic coronal N/Fe ratio (G1)phys.abundfloatnullable[O/Fe]corLogarithmic coronal O/Fe ratio (G1)phys.abundfloat