J/ApJ/830/44ivo://CDS.VizieR/J/ApJ/830/44doi:10.26093/cds/vizier.18300044CDSNunez A.Agueros M.A.2025-01-28T20:09:48Z2017-02-17T07:32:29ZCDS support team

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

cds-question@unistra.fropen-star-clustersstellar-massesx-ray-sourcesWe use a 440.5ks Chandra observation of the ~500Myr old open cluster M37 to derive the X-ray luminosity functions of its <=1.2M_{sun}_ stars. Combining detections of 162 M37 members with upper limits for 160 non-detections, we find that its G, K, and M stars have a similar median (0.5-7keV) X-ray luminosity L_X_=10^29.0^erg/s, whereas the L_X_-to-bolometric-luminosity ratio (L_X_/L_bol_) indicates that M stars are more active than G and K stars by ~1 order of magnitude at 500Myr. To characterize the evolution of magnetic activity in low-mass stars over their first ~600Myr, we consolidate X-ray and optical data from the literature for stars in six other open clusters: from youngest to oldest they are, the Orion Nebula Cluster (ONC), NGC 2547, NGC 2516, the Pleiades, NGC 6475, and the Hyades. For these, we homogenize the conversion of instrumental count rates to L_X_ by applying the same one-temperature emission model as for M37, and obtain masses using the same empirical mass-absolute magnitude relation (except for the ONC). We find that for G and K stars X-ray activity decreases ~2 orders of magnitude over their first 600Myr, and for M stars, ~1.5. The decay rate of the median L_X_ follows the relation L_X_{propto}t^b^, where b=-0.61+/-0.12 for G stars, -0.82+/-0.16 for K stars, and -0.40+/-0.17 for M stars. In L_X_/L_bol_ space, the slopes are -0.68+/-0.12, -0.81+/-0.19, and -0.61+/-0.12, respectively. These results suggest that for low-mass stars the age-activity relation steepens after ~625Myr, consistent with the faster decay in activity observed in solar analogs at t>1Gyr.2016ApJ...830...44Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/830/44CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)IX/50 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR6 (XMM-SSC, 2016)J/ApJ/822/47 : K2 rotation periods for 65 Hyades members (Douglas+, 2016)J/ApJ/809/161 : X-ray obs. and membership probabilities of M37 (Nunez+, 2015)J/ApJ/804/146 : Atmospheric parameters for nearby B-F stars (David+, 2015)J/A+A/566/A132 : Teff and L for stars in 7 open clusters (Silaj+, 2014)J/A+A/559/A43 : Pan-STARRS1 (PS1) observations of the Hyades (Goldman+, 2013)J/MNRAS/431/2063 : UV/X-ray activity of M dwarfs within 10pc (Stelzer+, 2013)J/MNRAS/407/465 : Fast-rotating M dwarfs in NGC2516 (Jackson+, 2010)J/A+A/490/113 : X-ray sources in NGC 752 (Giardino+, 2008)J/ApJ/675/1254 : M37 variable stars (Hartman+, 2008)J/ApJ/675/1233 : gri photometry in M37 (NGC 2099) (Hartman+, 2008)J/A+A/453/101 : UBV(RI)c photometry of 4 open clusters (Lyra+, 2006)J/A+A/450/993 : XMM survey of NGC 2516 (Pillitteri+, 2006)J/MNRAS/367/781 : XMM observations of NGC 2547 (Jeffries+, 2006)J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)J/MNRAS/358/13 : Faint dwarfs in NGC 2547 (Jeffries+, 2005)J/ApJ/601/979 : vsini of Orion low-mass stars (Wolff+, 2004)J/ApJ/588/1009 : Chandra X-ray observations of NGC 2516 (Damiani+, 2003)J/ApJ/584/911 : X-rays in the Orion nebula cluster (Feigelson+, 2003)J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)J/AJ/123/290 : UBVI CCD photometry of NGC 2516 (Sung+, 2002)J/A+A/345/471 : Memberships of open clusters (Robichon+, 1999)J/A+A/341/751 : ROSAT HRI observations of the Pleiades (Micela+ 1999)J/A+A/335/183 : Pleiades low-mass stars rotational velocities (Queloz+ 1998)J/A+A/331/81 : Hyades membership (Perryman+ 1998)J/AJ/110/1229 : ROSAT X-ray survey in NGC 6475 (Prosser+ 1995)J/ApJ/448/683 : Hyades RASS observations (Stern+ 1995)J/ApJS/91/625 : ROSAT survey of the Pleiades (Stauffer+ 1994)J/ApJ/315/687 : X-Ray emission from solar-type stars: F and G (Maggio+, 1987)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/830/44https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/830/44http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/830/44https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/830/44https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/830/44http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/830/44GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/830/44/table1 (M37 (NGC 2099) low-mass members in the field of view of Chandra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/830/44/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/830/44/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/830/44/table1?GETtext/xml+votable180.050000true88.21532.63966670.005555555555555556Cone search capability for table J/ApJ/830/44/table2 (Cluster characteristics and number of X-ray detections/non-detections)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/830/44/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/830/44/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/830/44/table2?GETtext/xml+votable180.050000true83.75-5.48333330.005555555555555556Cone search capability for table J/ApJ/830/44/table3 (Clusters members characteristics for the 6 other open clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/830/44/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/830/44/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/830/44/table3?GETtext/xml+votable180.050000true83.65928111-5.406533890.0055555555555555565/81 84 115 118 5875 5878 5881 5883-5884 5886-5887 6058 6/75 287 309 311 318 320 322-323 334 340-342 348 357 373 383 401 438 450 455-456 466-467 477-478 483-485 487 496 498 840 917 1024-1026 1031-1032 1035-1036 1042 1044-1045 1048 1050 1057-1058 1064 1075 1096 1198 1206 21438-21439 22805 23023 23286 23313 23321 23332 23355 23368 23400 23444 23450 23453 23478-23479 23490 23492-23494 23496 23498-23499 23504-23505 23511 23518-23520 23522-23523 23529 23531 23540-23542 24099 24104 24201-24204 24206-24207 24209 24212 24218-24219 24230 24242 24248 24252 24522 28710-28711 28717 28722 37592-37593 39181 39183https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/830/44?format=asciiX-raydefaultJ/ApJ/830/44/table1M37 (NGC 2099) low-mass members in the field of view of ChandraPapIDisplay data from Paper I: Nunez+, 2015, J/ApJ/809/161meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from Hartman+, 2008, J/ApJ/675/1233 or from Paper I (Nunez+, 2015, J/ApJ/809/161) for ID 130776 (right ascension part)degpos.eq.ra;meta.main_DEPositions from Hartman+, 2008, J/ApJ/675/1233 or from Paper I (Nunez+, 2015, J/ApJ/809/161) for ID 130776 (declination part)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBinBinarity flag (1=likely a binary member) (2)meta.codeintMass[0.2/1.2] Stellar masssolMassphys.massfloatlogLbol[31.7/34] Log bolometric luminosity, erg/s (2)log(1e-07W)phys.luminosityfloatf_logLXDetection flag (0=X-ray upper limit only) (3)meta.codeintID[30118/340096] Optical ID from Hartman+ (2008, J/ApJ/675/1233; <Cl* NGC 2099 HGH NNNNNN> in Simbad)meta.id;meta.mainintlogLX[28.4/30.5] Log X-ray luminosity (or upper limit luminosity), erg/s (G1)log(1e-07W)phys.luminosity;em.X-rayfloatPmem[0.3/1] Probability that object is member (1)meta.id.parent;stat.probabilityfloatJ/ApJ/830/44/table2Cluster characteristics and number of X-ray detections/non-detectionsNmmeta.numberintnullableClusterOpen cluster namemeta.id;meta.maincharprimarySimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintf_Cluster[e] Flag on Cluster (1)meta.codecharRefReference(s) (2)meta.ref;pos.framecharInstInstrument(s) (3)meta.id;instrcharlogLX[27.4/29] Minimum log X-ray luminosity detected in 0.5-7keV band, in erg/slog(1e-07W)phys.luminosity;em.X-rayfloatGDet[10/74] Number of G stars (0.8-1.2M_{sun}_) detectedmeta.numberintGnDet[0/59] Number of G stars non-detectedmeta.numberintKDet[7/58] Number of K stars (0.6-0.8M_{sun}_) detectedmeta.numberintKnDet[0/89] Number of K stars non-detectedmeta.numberintMDet[6/138] Number of M stars (0.1-0.6M_{sun}_) detectedmeta.numberintMnDet[0/174] Number of M stars non-detectedmeta.numberintlogAge[6.4/8.8] Log Agelog(yr)time.agefloatf_logAge[f] Flag on logAge (1)meta.codecharDist[47/1490] Distancepcpos.distance;pos.heliocentricfloatf_Dist[f] Flag on Dist (1)meta.codecharl_logNHLimit flag on NHmeta.code.errorcharlogNH[20/22] Atomic neutral hydrogen column densitylog(cm**-2)phys.columnDensityfloatf_logNH[f] Flag on logNH (1)meta.codecharE(B-V)[0/0.3]? Reddeningmagphot.color.excessfloatnullablef_E(B-V)[g] Flag on E(B-V) (1)meta.codechar_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/ApJ/830/44/table3Clusters members characteristics for the 6 other open clustersRAJ2000Right ascension of object (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of object (J2000)degpos.eq.dec;meta.mainClusterOpen cluster to which object belongs (the ONC, NGC 2547, NGC 2516, NGC 6475, the Pleiades and the Hyades)meta.id.parentcharMass[0.1/1.2] Stellar mass (1)solMassphys.massfloatlogLbol[30/35] Log of Bolometric luminosity, erg/s (2)log(1e-07W)phys.luminosityfloatDist[31/414] Distance to objectpcpos.distance;pos.heliocentricfloatNH[1/912.1]? Atomic neutral hydrogen column density (3)1e+20cm**-2phys.columnDensityfloatnullablef_logLXDetection flag (0=X-ray upper limit only)meta.codeintlogLX[27.5/31.5] Log of X-ray luminosity (or upper limit luminosity), erg/s (G1)log(1e-07W)phys.luminosity;em.X-rayfloatSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameIdentifiermeta.id;meta.mainchar