J/MNRAS/332/441ivo://CDS.VizieR/J/MNRAS/332/441doi:10.26093/cds/vizier.73320441CDSFormiggini L.Brosch N.Almoznino E.Bowyer S.Lampton M.2024-06-27T20:18:12Z2006-09-25T08:55:15ZCDS support team

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

cds-question@unistra.frwhite-dwarf-starsultraviolet-astronomyphotometryvisible-astronomytrigonometric-parallaxproper-motionsWe present results of an analysis of a UV image in the direction of Ophiuchus, obtained with the FAUST instrument. The image contains 228 UV sources. Most of these are identified as normal early-type stars through correlations with catalogued objects. For the first time in this project we identify UV sources as such stars by selecting suitable candidates in crowded fields as the bluest objects in colour-colour diagrams using observations from the Wise Observatory. These candidates are then studied using low-resolution spectroscopy, which allows the determination of spectral types to an accuracy of about one-half class, for 60 stars. Synthetic photometry of spectral data is performed in order to predict the expected UV emission, on the basis of the photometric information. These results are used along with the Hipparcos/Tycho (<I/239>) information, to search for subluminous stars. The comparison of the predicted emission with the FAUST measured magnitudes allows us to select 12 stars as highly probable evolved hot stars. High signal-to-noise spectra are obtained for nine of these stars, and Balmer line profiles are compared with the prediction of atmosphere models and with the spectrum of real stellar atmospheres. Among the nine candidates, six are classified as previously unrecognized sdB stars, and two as white dwarfs. Our result indicates that indeed more bright subluminous stars are still unrecognized in the existing samples.2002MNRAS.332..441Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/332/441CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/239 : The Hipparcos and Tycho Catalogues (ESA 1997)J/A+A/372/173 : ISOCAM observations of rho Ophiuchi cloud (Bontemps+, 2001)J/ApJ/438/813 : Stellar population in {rho} Oph cloud core (Strom+, 1995)J/ApJ/566/993 : HST/NICMOS survey of Ophiuchus cloud (Allen+, 2002)J/ApJS/96/461 : Far-UV Point Sources from FAUST (Bowyer+ 1995)J/ApJS/104/101 : Far-UV stellar photometry (Schmidt+, 1996)J/ApJS/112/109 : Rho Oph Near IR Positions and Photometry (Barsony+, 1997)J/MNRAS/316/326 : Redshifts of Ophiuchus region galaxies (Hasegawa+, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/332/441https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/332/441http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/332/441https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/332/441https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/332/441http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/332/441GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/332/441/table1 (Derived FAUST sources in the Ophiuchus field)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/332/441/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/332/441/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/332/441/table1?GETtext/xml+votable180.050000true263.7185833-16.64651110.005555555555555556Cone search capability for table J/MNRAS/332/441/table2 (Identified FAUST sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/332/441/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/332/441/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/332/441/table2?GETtext/xml+votable180.050000true263.69575-16.62386110.0055555555555555564/1830 5/7303 7309 7311 7314-7315 7324 7326 7333 7344-7345 6/29207 29209 29211 29233-29235 29240-29241 29243 29250-29251 29274 29329 29341 29384-29385 29387-29389 29392-29394https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/332/441?format=asciiUVOpticaldefaultJ/MNRAS/332/441/table1Derived FAUST sources in the Ophiuchus fieldrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[FBA2002]Identification (sequential number)meta.id;meta.mainintprimaryRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainUVmagFAUST UV magnitudemagphot.mag;em.UVfloate_UVmagrms uncertainty on UVmagmagstat.error;phot.mag;em.UVfloatFAUST? FAUST numbermeta.idintnullableJ/MNRAS/332/441/table2Identified FAUST sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[FBA2002]Identification (sequential number)meta.id;meta.mainintn_[FBA2002][*] * indicates two identifications proposedmeta.notecharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainIDProposed star identificationmeta.idcharSpTypeMK spectral typesrc.spTypecharl_BmagLimit flag on Bmagmeta.code.error;phot.mag;em.opt.BcharBmag? Blue magnitudemagphot.mag;em.opt.BfloatnullableVmag? Visual magnitudemagphot.mag;em.optfloatnullableJ/MNRAS/332/441/table4Hipparcos datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[FBA2002]Identification (sequential number)meta.id;meta.mainintn_[FBA2002][*] * indicates two identifications proposedmeta.notecharplxTycho (<I/239>) parallaxmaspos.parallax.trigfloate_plxrms uncertainty on plxmasstat.error;pos.parallaxfloatDistDerived distancepcpos.distancefloatl_VMAGLimit flag on VMAGmeta.code.errorcharVMAGDerived absolute V magnitudemagphys.magAbs;em.opt.VfloatSpTypeMK spectral typesrc.spTypecharpmRA? Proper motion in right ascensionmas/yrpos.pm;pos.eq.rafloatnullablee_pmRA? rms uncertainty on pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatnullablepmDE? Proper motion in declinationmas/yrpos.pm;pos.eq.decfloatnullablee_pmDE? rms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatnullableJ/MNRAS/332/441/table5Candidates subluminous starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[FBA2002]Identification (sequential number)meta.id;meta.mainintSpTypeMK spectral typesrc.spTypecharVmagVisual magnitudemagphot.mag;em.optfloatplxParallaxmaspos.parallax.trigfloate_plxrms uncertainty on plxmasstat.error;pos.parallaxfloatE(UV)UV-excessmagphot.color.excessfloatClassNew classificationmeta.code.classchar