J/ApJ/437/361ivo://CDS.VizieR/J/ApJ/437/361doi:10.26093/cds/vizier.14370361CDSGagne M.Caillault J.-P.2000-11-07T13:40:23Z2000-11-07T14:38:48ZCDS support team

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

cds-question@unistra.frx-ray-sourcesnebulaeWe have analyzed archival Einstein Observatory images of a roughly 4.5 square degree region centered on the Orion Nebula. In all, 245 distinct X-ray sources have been detected in six High Resolution Imager (HRI) and 17 Imaging Proportional Counter (IPC) observations. An optical database of over 2700 stars has been assembled to search for candidate counterparts to the X-ray sources. Roughly half the X-ray sources are identified with a single Orion Nebula cluster member. The 10 main-sequence O6-B5 cluster stars detected in Orion have X-ray activity levels comparable to field O and B stars. X-ray emission has also been detected in the direction of four main-sequence late-B and early-A type stars. Since the mechanisms producing X-rays in late-type coronae and early-type winds cannot operate in the late-B and early-A type atmospheres, we argue that the observed X-rays, with L_X_~3x10^30^ergs/s, are probably produced in the coronae of unseen late-type binary companions. Over 100 X-ray sources have been associated with late-type pre-main sequence stars.1994ApJ...437..361Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/437/361CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/171 : Parenago Catalogue of stars in Orion Nebula area (1954)II/36 : Photometry of Orion OB1 Association (Warren+ 1977)J/ApJ/445/280 : ROSAT survey of the Orion nebula region (Gagne+ 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/437/361https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/437/361http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/437/361https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/437/361https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/437/361http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/437/361GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/437/361/table2 (Sources detected in the Orion Nebula Region by Einstein)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/437/361/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/437/361/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/437/361/table2?GETtext/xml+votable180.050000true83.041552-5.0397760.005555555555555556Einstein5/5359 6/21427 21430 21433 21435 22804 22805 22807 22848https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/437/361?format=asciiX-raydefaultJ/ApJ/437/361/table2Sources detected in the Orion Nebula Region by EinsteinrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoXX-ray numbermeta.id;meta.mainintprimaryRAB1950Right ascension (B1950) of the sourcepos.eq.ra;meta.mainDEB1950Declination (B1950) of the sourcepos.eq.dec;meta.mainRate1? IPC count ratect/sphot.count;em.X-raydoublenullablee_Rate1? rms uncertainty on Rate1ct/sstat.errordoublenullableRate2? HRI count ratect/sphot.count;em.X-raydoublenullablee_Rate2? rms uncertainty on Rate2ct/sstat.errordoublenullableDRA? Offset in right ascensionarcsecpos.eq.ra;arith.diffintnullableDDE? Offset in declinationarcsecpos.eq.dec;arith.diffintnullableNameStar namemeta.idcharn_Name[*] * indicates multiple optical counterpart. See table3meta.notecharProb? Membership probabilitystat.fit.goodnessintnullableJ/ApJ/437/361/table3Einstein sources with multiple optical counterpartsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoXX-ray numbermeta.id;meta.mainintprimaryoRA1Offset in right ascension for star1arcsecpos.eq.ra;arith.diffintoDE1Offset in declination for star1arcsecpos.eq.dec;arith.diffintStar1Star1 namemeta.idcharProb1? Membership probability for star1stat.fit.goodnessintnullableoRA2Offset in right ascension for star2arcsecpos.eq.ra;arith.diffintoDE2Offset in declination for star2arcsecpos.eq.dec;arith.diffintStar2Star2 namemeta.idcharProb2? Membership probability for star2stat.fit.goodnessintnullableoRA3? Offset in right ascension for star3arcsecpos.eq.ra;arith.diffintnullableoDE3? Offset in declination for star3arcsecpos.eq.dec;arith.diffintnullableStar3Star3 namemeta.idcharProb3? Membership probability for star3stat.fit.goodnessintnullableJ/ApJ/437/361/table6Optical and X-ray data for typed cluster membersNoteIndividual Notes (file notes.dat)meta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoXX-ray numbermeta.id;meta.mainintprimaryParParenago (1954, Cat.<II/171>) designationmeta.idcharJ+WJones & Walker (1988) designationmeta.idcharGCVSGCVS designationmeta.idcharSpSpectral typesrc.spTypecharlogTeffEffective temperaturelog(K)phys.temperature.effectivefloatBmag? B magnitudemagphot.mag;em.opt.BfloatnullableVmag? V magnitudemagphot.mag;em.opt.VfloatnullableIcmag? Ic magnitudemagphot.mag;em.opt.IfloatnullablelogLXX-ray luminositylog(1e-07W)phys.luminosity;em.X-rayfloatlog(LX/Lbol)? X-ray luminosity versus bolometric luminosity ratiophys.luminosity;arith.ratiofloatnullableJ/ApJ/437/361/table7Optical and X-ray data for untyped cluster membersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoXX-ray numbermeta.id;meta.mainintprimaryParParenago (1954, Cat.<II/171>) designationmeta.idcharJ+WJones & Walker (1988) designationmeta.idcharGCVSGCVS designationmeta.idcharBmag? B magnitudemagphot.mag;em.opt.BfloatnullableVmag? V magnitudemagphot.mag;em.opt.VfloatnullableIcmag? Ic magnitudemagphot.mag;em.opt.IfloatnullablelogLXX-ray luminositylog(1e-07W)phys.luminosity;em.X-rayfloatn_logLX[b] Note on LX (1)meta.notecharlog(fX/fbol)? X-ray flux versus bolometric flux ratiophot.flux;arith.ratiofloatnullableNoteIndividual Notes (file notes.dat)meta.notecharJ/ApJ/437/361/table8Rotational and X-ray data for late-type cluster membersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoXX-ray numbermeta.id;meta.mainintprimaryParParenago (1954, Cat.<II/171>) designationmeta.idcharJ+WJones & Walker (1988AJ.....95.1755J) designationmeta.idcharGCVSGCVS designationmeta.idcharSpSpectral typesrc.spTypecharlogLXX-ray luminositylog(1e-07W)phys.luminosity;em.X-rayfloatlogFXX-ray fluxlog(mW.m**-2)phot.flux;em.X-rayfloatu_logFXUncertainty flag on logFXmeta.code.errorcharl_vsiniLimit flag on vsinimeta.code.errorcharvsini? Rotational velocitykm/sphys.veloc.rotatintnullableProt? Period of rotationdtime.periodfloatnullableNoteIndividual Notes (1)meta.notecharJ/ApJ/437/361/notesNotes to tables 6 and 7recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoteNote symbol (tables 6 and 7)meta.notecharTextText of note (includes the bibcode)meta.notechar