J/AJ/161/277ivo://CDS.VizieR/J/AJ/161/277doi:10.26093/cds/vizier.51610277CDSKiman R.Faherty J.K.Cruz K.L.Gagne J.Angus R.Schmidt S.J.,Mann A.W.Bardalez Gagliuffi D.C.Rice E.2021-12-07T21:30:14Z2021-09-09T07:00:05ZCDS support team

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

cds-question@unistra.frm-starsdwarf-starsvisible-astronomyh-alpha-photometrystellar-spectral-typesIn this work, we calibrate the relationship between H{alpha} emission and M-dwarf ages. We compile a sample of 892 M-dwarfs with H{alpha} equivalent width (H{alpha}EW) measurements from the literature that are either comoving with a white dwarf of known age (21 stars) or in a known young association (871 stars). In this sample we identify 7 M-dwarfs that are new candidate members of known associations. By dividing the stars into active and inactive categories according to their H{alpha}EW and spectral type (SpT), we find that the fraction of active dwarfs decreases with increasing age, and the form of the decline depends on SpT. Using the compiled sample of age calibrators, we find that H{alpha} EW and fractional H{alpha} luminosity (L_H{alpha}_/L_bol_) decrease with increasing age. H{alpha}EW for SpT<~M7 decreases gradually up until ~1Gyr. For older ages, we found only two early M dwarfs that are both inactive and seem to continue the gradual decrease. We also found 14 mid-type M-dwarfs, out of which 11 are inactive and present a significant decrease in H{alpha}EW, suggesting that the magnetic activity decreases rapidly after ~1Gyr. We fit L_H{alpha}_/L_bol_ versus age with a broken power law and find an index of -0.11_-0.01_^+0.02^ for ages <~776Myr. The index becomes much steeper at older ages, but a lack of field age-calibrators (>>1Gyr) leaves this part of the relation far less constrained. Finally, from repeated independent measurements for the same stars, we find that 94% of them have a level of H{alpha}EW variability <~5{AA} at young ages (<1Gyr).2021AJ....161..277Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/161/277CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/447/1126 : Halpha measurements in Abell 2465 (Wegner+, 2015)J/MNRAS/466/163 : Candidate Halpha sources in GBS (Wevers+, 2017)J/A+A/624/A10 : Normalized Halpha line profiles of FGK stars (Giribaldi+, 2019)J/A+A/630/A90 : Halpha emission-line stars in Canis Major (Pettersson+, 2019)J/ApJS/253/19 : Halpha and other EWs of LAMOST M-type stars (Zhang+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/161/277https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/161/277http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/161/277https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/161/277https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/161/277http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/161/277GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/161/277/table3 (*H{alpha}EW outliers)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/161/277/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/161/277/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/161/277/table3?GETtext/xml+votable180.050000true165.4662725-34.70473110.0055555555555555566/1052 1074 5282 9949 22884-22885 23509 23717 24629 24763 26416 28132 33737 34885 37013 38191 38347 38359 38382 39792 41130 41472 42959 42981 42985-42986 42988 43002 43670 44317 44358 44363 44366-44367 44378-44379 44389 44401 46087https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/161/277?format=asciiOpticaldefaultJ/AJ/161/277/table3*H{alpha}EW outliers2MASS2MASS identifiermeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpT? Spectral typesrc.spTypefloatnullableEWHa[11.5/250] Equivalent width, H{alpha}0.1nmspect.line.eqWidthdoublee_EWHa[0.05/9.8]? Uncertainty in EWHa0.1nmstat.errordoublenullabledHa[0.43/230] Delta above the H{alpha} EW limitstat.fit.omc;phys.energyfloatSimbadSimbad 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.main