J/AJ/111/439ivo://CDS.VizieR/J/AJ/111/439doi:10.26093/cds/vizier.51110439CDSHenry T.J.Soderblom D.R.Donahue R.A.Baliunas S.L.2023-04-06T16:50:20Z2004-03-26T14:13:42ZCDS support team

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

cds-question@unistra.frstellar-atmospheresphotometrylate-type-starsMore than 800 southern stars within 50pc have been observed for chromospheric emission in the cores of the Ca II H and K lines. Most of the sample targets were selected to be G dwarfs on the basis of colors and spectral types. The bimodal distribution in stellar activity first noted in a sample of northern stars by Vaughan and Preston (1980PASP...92..385V) is confirmed, and the percentage of active stars, about 30%, is remarkably consistent between the northern and southern surveys. This is especially compelling given that we have used an entirely different instrumental setup and stellar sample than used in the previous study. Comparisons to the Sun, a relatively inactive star, show that most nearby solar-type stars have a similar activity level, and presumably a similar age. We identify two additional subsamples of stars -- a very active group, and a very inactive group. The very active group may be made up of young stars near the Sun, accounting for only a few percent of the sample, and appears to be less than ~0.1Gyr old. Included in this high-activity tail of the distribution, however, is a subset of very close binaries of the RS CVn or W UMa types. The remaining members of this population may be undetected close binaries or very young single stars. The very inactive group of stars, contributing ~5%-10% to the total sample, may be those caught during a Maunder Minimum type phase. If the observations of the survey stars are considered to be a sequence of snapshots of the Sun during its life, we might expect that the Sun will spend about 10% of the remainder of its main sequence life in a Maunder Minimum phase.1996AJ....111..439Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/111/439CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/111/439https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/111/439http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/111/439https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/111/439https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/111/439http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/111/439GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/111/439/table4 (Chromospheric activity observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/111/439/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/111/439/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/111/439/table4?GETtext/xml+votable180.050000true1.28123-52.1517410.0055555555555555565/11808 6/137 684 5377 8790 8995 12592 12846 12944 13301 16386 16408 16422 16440 16448 16457 16463 16506 16518-16519 16532 16540 16577 16652 16678-16679 16912 16930-16931 17017 17137 17219 17425 17486 17606 18139 20145 20545 20548 20557 20593 20600 20621 20633 20640-20641 20653 20665 20746 20753 21060 21177 22157 22708 24581 24585 24620 24625 24628 24633-24634 24713 24729 24731 24736 24769 24902 24924 24990 25102 25113 25966 26462 26521 28675 28690 28696 28715 28719 28760 28815 28841 28868 28875 28882 28934 28947 28960-28961 28968 28987 29190 29196 29422 31073 31130 31433 31478 31751 31768 32067 32549 32800 32802 32812 32842 32848 32860 32921 32930 32998-32999 33042 33082 33122 33160 33201 33224 33252 33281 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45175 45182 45238 45241 45253 45265 45272 45299 45337 45343 45345 45350 45353 45360 45378 45382 45388 45396 45412 45430 45432 45458 45472 45527 45535 45541 45551 45564 45621 45627 45639 45641 45653-45654 45668-45669 45673 45687 45770 45799 45811 45865 45874 45888 45917 45927 45929 45944 45948 45956 45982 45986 45992 46056 46065 46076 46080 46100 46112 46115 46129 46135 46170 46172 46191 46193 46208 46234 46247-46248 46277 46287 46297 46306 46320 46325 46342 46355 46394 46467 46472-46473 46482 46501 46523 46526 46593 46625-46627 46640 46654-46655 46681-46682 46685 46708 46728 46734 46777 46790 46800 46820 46874 46910 46916 46923 46925 46944 46967 46977 46991-46992 46998 47001 47027 47045 47073 47107 47114 47127 47133 47137 47149 47176 47205 47213 47274 47279 47287 47311 47360-47361 47377 47409 47429-47430 47461 47502 47543 47550 47576 47584 47589-47590 47606 47629 47702 47706 47710 47730 47740 47742 47745 47791 47824 47830 47842 47858 47894 47903-47904 47910 47919 47930 47935 47945 47949 47953 47975 47985 47991 48004 48007 48014-48015 48022 48176 48182 48199 48212 48223 48230 48240 48249 48254 48259 48277 48283 48291 48305 48335 48394 48656 48664 48672 48705https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/111/439?format=asciiOpticaldefaultJ/AJ/111/439/table4Chromospheric activity observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHD[1/225300] Henry Draper numbermeta.id;meta.mainintprimarym_HDComponent(s) of HD numbermeta.code.multipcharNote[0123*] Coded notemeta.notecharMultMultiplicity informationmeta.code.multipcharRef[BDGHIJW] Coded reference for Multmeta.refcharSample[BCNPSX ] Coded sample informationmeta.notecharVmagV magnitudemagphot.mag;em.opt.Vfloate_VmagError in Vmagmagstat.errorfloatB-V(B-V) colormagphot.color;em.opt.B;em.opt.Vfloate_B-VError in B-Vmagstat.errorfloatMRefCoded reference for V and B-Vmeta.refcharDateUT date of observation (ddmmyy)time.epochnullableFlagFlag indicating special status of obs.meta.codecharS(CTIO)? S value from CTIO observationspect.indexfloatnullableS(MW)? S value converted to Mt. Wilson systemspect.indexfloatnullablelogR'(HK)? Log R'(HK) valuespect.indexfloatnullableNobs? Number of observationsmeta.numberintnullablelogR'(HK)m? Mean log R' value of observationsspect.indexfloatnullablee_logR'(HK)m? Error in logR'(HK)mstat.errorfloatnullableSimbadSimbad column added by the CDSmeta.refchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/AJ/111/439/notesNotes on individual objects in table 4TextText of notemeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDStarmeta.id;meta.mainint