J/AJ/160/217ivo://CDS.VizieR/J/AJ/160/217doi:10.26093/cds/vizier.51600217CDSCrandall S.Smith G.H.Subramonian A.Ho K.Cochrane E.M.2021-09-28T09:37:30Z2021-02-05T08:50:00ZCDS support team

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

cds-question@unistra.frdwarf-starsf-starsultraviolet-photometryvisible-astronomystellar-agestwo-color-diagramsStellar age cannot be directly measured, yet age determinations are fundamental to understanding the evolution of stars, planets, and galaxies. The work presented here builds upon the idea of a stellar-activity age. We utilized far-ultraviolet (FUV) photometry acquired by the Galaxy Evolution Explorer (GALEX) space telescope as an indicator of chromospheric activity to infer ages of late-F, G, and K type dwarf stars. We derived a purely empirical correlation between FUV magnitudes and stellar age in conjunction with (B-V) color. Our attention is restricted to Sun-like stars with color range 0.55<=(B-V)<=0.71 and absolute magnitude range 4.3<=MV<=5.3. The correlation is defined in terms of a FUV-excess parameter Q(FUV-B,B-V). We related stellar age, {tau}, to Q through the relation log_e_({tau})=log_e_(a)+bQ, where a and b are fit parameters and functions of (B-V). This correlation is functional up to 6Gyr for FGK dwarfs. With such a correlation, one only needs Johnson (B-V) and FUV measurements to estimate the stellar age for Population i dwarf stars of solar-like temperature and metallicity. Such a calibration has utility in population studies of FGK dwarfs for further understanding of the chemical evolution of the Milky Way. As an illustration of one such application, we have constructed activity and FUV-age distributions for a sample of thin and thick disk stars, as distinguished by their chemical abundances. Considerable overlap is found between the activity distribution and age range of the two populations. We discuss the possibility that some high-[{alpha}/Fe] thick disk stars were formed as a result of the accretion of dwarf galaxies as recently as 4Gyr ago.2020AJ....160..217Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/160/217CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/simbad : Simbad objects catalogue (M.Wenger 2000)V/117 : Geneva-Copenhagen Survey of Solar neighbourhood (Holmberg+, 2007)J/PASP/106/281 : Photometry and radial velocities in NGC752 (Daniel+, 1994)J/AJ/119/1760 : M54 and Sgr dSph VI photometry (Layden+, 2000)J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)J/AJ/133/270 : Metallicities and ages in Leo II dSph (Koch+, 2007)J/A+A/484/815 : Scaled solar tracks and isochrones (Bertelli+, 2008)J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)J/A+A/508/355 : Scaled solar tracks and isochrones (Bertelli+, 2009)J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)J/MNRAS/422/2024 : X-ray-age relation and exoplanet evaporation (Jackson+,2012)J/ApJ/775/55 : Spitzer IR excesses in A-K stars (Ballering+, 2013)J/ApJ/785/33 : High quality Spitzer/MIPS obs. F4-K2 stars (Sierchio+, 2014)J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)J/A+A/606/A94 : Chemical abundances of 1059 FGK stars (Delgado Mena+, 2017)J/A+A/619/A73 : Solar Twins age-chromo. activity (Lorenzo-Oliveira+, 2018)J/ApJ/862/33 : Improved & expanded member. catalog NGC752 (Agueros+, 2018)J/ApJ/861/153 : Ultraviolet Extinction in the GALEX Bands. UVEXT (Sun+,2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/160/217https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/160/217http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/160/217https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/160/217https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/160/217http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/160/217GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/160/217/table3 (Properties of field Star used in FUV-Age calibration)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/160/217/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/160/217/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/160/217/table3?GETtext/xml+votable180.050000true1.4689372-41.75306830.005555555555555556Cone search capability for table J/AJ/160/217/table5 (Thick and thin disk constituents)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/160/217/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/160/217/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/160/217/table5?GETtext/xml+votable180.050000true45.9123283-5.66629750.0055555555555555566/75 86 188 322 356 719 742 819 871 944 1028 1058 2072 2491 2652 3691 3780 4313 4665 4867 4912 4993 5073-5074 5108 5160 5304 5327 5413 5476 5522 5587 5701 5789 5858 6078 6087 6217 6269 6308 6325 6409 6522-6523 6699 6790 6926 6932 6971 7052 7299 7485 7763 7933 7978 8184 8244 8255 8286 8319 8466 8700 8792 8995 9391 9404 9480 9492 9537 9883 10140 10350 10400 10598 10812 11008 11014 11128 11150 11355 11538 11856 11946 12058 12146 12203 12341 12343 12512 12592 12644 12792 12890 13106 13650 13900 14089 14155 14502 15007 15030 15221 15864 15887 16652 16883 16930-16931 17177 17218-17219 17249 17266 17301 17341 17419 17435 17529 17572 17587 17619 17641 17657 17804 17929 17944 17954 18184 18209 18366 18373 18548 18623 18785 18835 18963 19003 19291 19491 19509 19796 19900 19923 20127 20145 20716 21121 21177 21326 21779 21809 21940 22313 22630 22746 22764 22779 23097 23150 23177 23342 23429 23511 23529 23537 23544-23545 23873 24254 24729 24769 25078 25136 25192 25424 25435 25527 25567 25578 25636 25755 25826 25966 26160 26256 26270 26488 26496 26626 26652 26888 27018 27254-27255 27395 27616 27661 27728 27750 27926 28041 28180 28342 29238 29410 29598 29675 29842 29900 30127 30378 30848 30943 31027 31104 31132 31433 31667 31860 31920 31945 32035 32575 32585 32787 32848 32998 33082 33160 33219 33252 33357 33400 33510 33590 33630 33879 33890 34204 34219 34308 34350 34372 34442 34564 34597 34638 34717 34856 34983 35214 35230 35442 35468 35497 35502 35590 35784 35811 35858 35885 35954 35968 35994 36029 36285 36453 36487 36517 36540 36635 36813 36969 36971 38260 38279 38339 38698 38706 38742 38788 38792 38807 38905 38955 39074 39461 39570 39576 39584 39984 40197 40442 40921 40932 41094 41143 42906 43258 43290 43567 43672 43724 43760 43845 43911 44131 44243 44740 44887 45034 45107 45143 45299 45430 45446 45457 45502 45627 45640 45668 45837 45948 46056 46076 46170 46193 46234 46247-46248 46287 46297 46306 46355 46487 46494 46511 46526 46558 46640 46681 46685 46734 46776 47073 47194 47308 47629 47647 47930 47935 47985 48230 48260 48345 48350 48362 48394 48402 48519 48607 48736 48821 48865 48870 48943 48980 49028 49097 49114https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/160/217?format=asciiUVOpticaldefaultJ/AJ/160/217/table3Properties of field Star used in FUV-Age calibrationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintr_NameSource catalog (1)meta.ref;pos.framecharNameName in HD catalogmeta.id;meta.maincharVmag[5.03/9.61] V band magnitudemagphot.mag;em.opt.VfloatB-V[0.55/0.7] Color, B-Vmagphot.color.excessfloatFUV-B[9.72/12.59] Color, FUV-Bmagphot.color.excessfloatQ[-2.83/-0.41] FUV-excess parameter determined by Equation 2phot.color.reddFreefloatAge[0.1/9] Literature quoted age (2)Gyrtime.agefloatSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPosition from SIMBAD (right ascension part)degpos.eq.ra;meta.main_DEPosition from SIMBAD (declination part)degpos.eq.dec;meta.mainJ/AJ/160/217/table5Thick and thin disk constituentsSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPosition from SIMBAD (right ascension part)degpos.eq.ra;meta.main_DEPosition from SIMBAD (declination part)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName in HD catalog (1)meta.id;meta.maincharB-V[0.58/0.68] Color, B-Vmagphot.color.excessfloatFUVmag[17.39/21.81] FUV magnitudemagphot.mag;em.UVfloata/Fe[-0.16/0.78] Abundance, {alpha} elements to ironphys.abundfloatQ[-2.26/0.19] FUV-excess parameter determined by Equation 2phot.color.reddFreefloatDiskThin (154 occurrences) or Thick (20 occurrences) diskmeta.codechar