J/A+A/364/205ivo://CDS.VizieR/J/A+A/364/205doi:10.26093/cds/vizier.33640205CDSCutispoto G.Pastori L.Guerrero A.Tagliaferri G.Messina S.,Rodono M.de Medeiros J.R.2001-01-31T07:49:06Z2001-01-31T08:48:51ZCDS support team

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

cds-question@unistra.frvisible-astronomybroad-band-photometrylate-type-starsx-ray-sourcesradial-velocityWe present high-precision photometry, high- and medium-resolution spectroscopy for a sample of 32 stars likely to be the optical counterparts of X-ray sources serendipitously detected by the EXOSAT satellite. Using also recent results from the Hipparcos satellite, we infer spectral types, compute X-ray luminosities and Li abundances and investigate the single or binary nature of the sample stars. We found eleven new variable stars, whose photometric periods fall in the 1.2-27.5 day range, for most of which the optical variability is consistent with the presence of photospheric cool spots. For our sample of X-ray selected stars we confirm the existence of a strong correlation between the stellar rotation rate and the level of activity, and also between the X-ray and bolometric luminosities. Two stars in our sample are likely to be pre-main sequence objects, one is likely to be a previously unknown M-type star within 25pc.2000A&A...364..205Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/364/205CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+AS/115/41 : UBV(RI)c photometry of cool stars. (Cutispoto, 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/364/205https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/364/205http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/364/205https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/364/205https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/364/205http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/364/205GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/364/205/stars (Star positions and magnitudes (from Simbad))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/364/205/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/364/205/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/364/205/stars?GETtext/xml+votable180.050000true350.0962516.7897220.0055555555555555566/686 940 1505 3063 4695 4859 5423 5581 6209 6340 9354 10420 10519 10938 12983 13216 13778 15014 15091 15094 16034 16059 17753 20020 20023 23477 23547-23548 24297 25851 26555 28060https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/364/205?format=asciiX-rayOpticaldefaultJ/A+A/364/205/starsStar positions and magnitudes (from Simbad)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject namemeta.id;meta.maincharprimarySimbadask the SIMBAD data-base about this objectmeta.refcharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainBmag? B magnitudemagphot.mag;em.opt.BfloatnullableVmag? V magnitudemagphot.mag;em.opt.VfloatnullableSpTypeSpectral typesrc.spTypecharJ/A+A/364/205/ubvmagComplete UBV data setrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharHJDHeliocentric Julian Daydtime.epochdoubleVmagV-band magnitudemagphot.mag;em.opt.VfloatB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.VfloatnullableU-B? U-B colour indexmagphot.color;em.opt.U;em.opt.BfloatnullableJ/A+A/364/205/ymagComplete y-band data setrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharHJDHeliocentric Julian Daydtime.epochdoubleymagStromgren y-band star-comparison differential magnitude in the instrumental systemmagphot.mag;em.opt.Vfloate_ymagrms uncertainty on ymagmagstat.errorfloatJ/A+A/364/205/table2Summary of stellar datan_SpType[2] Note on SpType (1)meta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharn_Name[*] *: faint stars whose spectral types were evaluated from photographic plates datameta.notecharVmagV-band magnitudemagphot.mag;em.opt.Vfloatu_VmagUncertainty flag on Vmagmeta.code.errorcharSpTypespectral type inferred by ussrc.spTypecharDistTrigonometric or photometric (n_Dist = ":") distancepcpos.distanceintn_Dist[:] ':' for photometric distancemeta.notecharl_EWLiLimit flag on EWLimeta.code.errorcharEWLi? Li I 6708 equivalent widthpmspect.line.eqWidthfloatnullablen_EWLi[yn 1] Note on EWLI (1)meta.notecharHalpha[ae pf] H alpha line detection flag (1)meta.codecharCaII[ae ?] Ca II H&K lines detection flag (1)meta.codecharl_PerLimit flag on Permeta.code.errorcharPer? Period of photometric variabilitydtime.periodfloatnullableu_Per[?] Uncertainty flag on Ppermeta.code.errorcharvsini? Rotational velocitykm/sphys.veloc.rotatintnullableu_vsiniUncertainty flag on vsinimeta.code.errorcharn_vsini[1/3] Note on vsinimeta.notecharlogLX? log of X-ray luminosity (in 10^30^erg/s) from the ROSAT PSPClog(1e+23W)phys.luminosity;em.X-rayfloatnullablelogLXe? log of X-ray luminosity (in 10^30^erg/s) from the EXOSAT CMAlog(1e+23W)phys.luminosity;em.X-rayfloatnullablel_logALiLimit flag on logALimeta.code.errorcharlogALi? Li abundance in logarithmic scale (H abundance = 12)phys.abundfloatnullablen_logALi[1] Note on logALi (1)meta.notecharJ/A+A/364/205/table3Radial velocitiesNameStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Daydtime.epochdoubleRVRadial velocity valuekm/sphys.veloc;pos.heliocentricfloate_RVrms uncertainty on RVkm/sstat.errorfloato_RVNumber of lines used for RV computationmeta.numberintSRSpectral region, Li (= Li I 6708) or Halphainstr.bandpasschar