J/A+A/464/581ivo://CDS.VizieR/J/A+A/464/581doi:10.26093/cds/vizier.34640581CDSKouwenhoven M.B.N.Brown A.G.A.Kaper L.2017-10-12T13:00:24Z2007-06-17T08:31:34ZCDS support team

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

cds-question@unistra.fropen-star-clustersmultiple-starsinfrared-photometryWe present JHK observations of 22 intermediate-mass stars in Sco OB2, obtained with NACO. This survey was performed to determine the status of (sub)stellar candidate companions of Sco OB2 member stars of spectral type A and late-B. The distinction between companions and background stars is made on the basis of a comparison to isochrones and additional statistical arguments. We include in our sample a subset of 9 targets with multi-color ADONIS observations from Kouwenhoven et al. (2005, Cat. <J/A+A/430/137>). We reanalyse the total sample (i.e. NACO and ADONIS) and conclude that of the 176 secondaries, 25 are physical companions, 55 are candidate companions, and 96 are background stars. Although we are sensitive (and complete) to brown dwarf companions as faint as K=14mag in the semi-major axis range 130-520AU, we detect only one, corresponding to a brown dwarf companion fraction of 0.5% (M>30M_Jupiter_). However, the number of brown dwarfs is consistent with an extrapolation of the (stellar) companion mass distribution into the brown dwarf regime. This indicates that the physical mechanism for the formation of brown dwarf companions around intermediate mass stars is similar to that of stellar companions, and that the embryo ejection mechanism does not need to be invoked in order to explain the small number of brown dwarf companions among intermediate mass stars in Sco OB2.2007A&A...464..581Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/464/581CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/239 : The Hipparcos and Tycho Catalogues (ESA 1997)J/A+A/430/137 : Close visual companions in Scorpius OB2 (Kouwenhoven+, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/464/581https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/464/581http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/464/581https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/464/581https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/464/581http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/464/581GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/464/581/table2 (Targets)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/464/581/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/464/581/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/464/581/table2?GETtext/xml+votable180.050000true183.0428169-63.45411470.005555555555555556Cone search capability for table J/A+A/464/581/tablea3 (Combined ADONIS/NACO results)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/464/581/tablea3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/464/581/tablea3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/464/581/tablea3?GETtext/xml+votable180.050000true154.7711311-64.67625780.0055555555555555566/29229 37242 37314 37928 37977 38145 41637 41726 41866 42218 42400 42407 42465 42610 42612 42617 42649 42670 42684 42714 42734 42808 42858 42959 42972 42978 42980 42985 42987 42989 42994 43012 43017 43032 43065 43093 43103 43153-43154 43157 43160 43206 43228 43323 43326 43332 43367 43377 43423 43523 43559 44054 44068 44088 44096 44136 44319 44352-44354 44361 44363 44378 44393 44400 44403 44409 44421https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/464/581?format=asciiInfrareddefaultJ/A+A/464/581/table2TargetsplxTrigonometric parallaxmaspos.parallax.trigfloate_plxParallax errormasstat.error;pos.parallaxfloatKsmagKs magnitudemagphot.mag;em.IR.KfloatSpTypeMK spectral typesrc.spTypecharGroupSubgroup (1)meta.notecharInstInstrument (ADONIS or NACO)meta.id;instrcharSimbadSimbad column added by the CDSchar_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.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHIPHipparcos numbermeta.id;meta.mainintprimaryHDHD numbermeta.idintHIPdataDisplay the HIP datameta.ref.urlcharJ/A+A/464/581/table4Confirmed companion starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHIPHipparcos numbermeta.id;meta.mainintm_HIP[1/12]? Secondary designationmeta.code.multipintnullableJmag? J magnitudemagphot.mag;em.IR.JfloatnullableHmag? H magnitudemagphot.mag;em.IR.HfloatnullableKsmag? Ks magnitudemagphot.mag;em.IR.Kfloatnullablerho? Angular separationarcsecpos.angDistancefloatnullablePA? Position angle (North to East)degpos.posAngfloatnullableJMAG? Absolute J magnitudemagphys.magAbs;em.IR.JfloatnullableStatusSecondary status (G1)meta.codecharInstInstrument (ADONIS or NACO)meta.id;instrcharRemarks[JHKjhkm! ] See note (2)meta.notecharHMAG? Absolute H magnitudemagphys.magAbs;em.IR.HfloatnullableKsMAG? Absolute Ks magnitudemagphys.magAbs;em.IR.KfloatnullableMass? Companion masssolMassphys.massfloatnullableJ/A+A/464/581/tablea1Results of NACO observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHIPHipparcos numbermeta.id;meta.mainintm_HIP[1/12]? Secondary designationmeta.code.multipintnullableJmag? J magnitudemagphot.mag;em.IR.JfloatnullableHmag? H magnitudemagphot.mag;em.IR.HfloatnullableKsmag? Ks magnitudemagphot.mag;em.IR.KfloatnullablePA? Position angle (North to East)degpos.posAngfloatnullableJMAG? Absolute J magnitudemagphys.magAbs;em.IR.JfloatnullableHMAG? Absolute H magnitudemagphys.magAbs;em.IR.HfloatnullableKsMAG? Absolute Ks magnitudemagphys.magAbs;em.IR.KfloatnullableMass? Companion masssolMassphys.massfloatnullableStatusSecondary status (G1)meta.codecharInstInstrument (ADONIS or NACO)meta.id;instrcharRemarks[JHKjhkm! ] See note (2)meta.notecharrho? Angular separationarcsecpos.angDistancefloatnullableJ/A+A/464/581/tablea2Background star criteriarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHIPHipparcos numbermeta.id;meta.mainintm_HIP[1/12] Secondary designationmeta.code.multipintStatusSecondary status (G1)meta.codecharX(J-K,MK)? Comparison with isochrone in (J-K,M_K) diagram (1)stat.fit.chi2floatnullableX(H-K,MK)? Comparison with isochrone in (H-K,M_K) diagram (1)stat.fit.chi2floatnullableX(J-H,MJ)? Comparison with isochrone in (J-H,M_J) diagram (1)stat.fit.chi2floatnullableInstInstrument (ADONIS or NACO)meta.id;instrcharRemarksLower limit flag (2)meta.notecharJ/A+A/464/581/tablea3Combined ADONIS/NACO resultsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHIPHipparcos numbermeta.id;meta.mainintprimaryJmag? J magnitudemagphot.mag;em.IR.JfloatnullableHmag? H magnitudemagphot.mag;em.IR.HfloatnullableKsmag? Ks magnitudemagphot.mag;em.IR.KfloatnullablerhoAngular separationarcsecpos.angDistancefloatPAPosition angle (North to East)degpos.posAngfloatStatusCompanion statusmeta.codecharDatesObserving datestime.epochcharADONISDisplay the ADONIS datameta.ref.urlcharHIPdataDisplay the HIP datameta.ref.urlcharSimbadSimbad column added by the CDSchar_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.main