J/A+A/515/A32ivo://CDS.VizieR/J/A+A/515/A32doi:10.26093/cds/vizier.35150032CDSAssafin M.Camargo J.I.B.Vieira Martins R.Andrei A.H.Sicardy B.,Young L.da Silva Neto D.N.Braga-Ribas F.2011-08-01T10:24:17Z2010-06-04T10:19:46ZCDS support team

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

cds-question@unistra.frastrometryoccultationsolar-system-planetsWe made the astrometry of 110GB of images with the Platform for Reduction of Astronomical Images Automatically (PRAIA). By relatively simple astrometric techniques, we treated the overlapping observations and derived a field distortion pattern for the WFI mosaic of CCDs to within 50mas precision. Positions were obtained in the UCAC2 frame with errors of 50mas for stars up to magnitude R=19, and 25mas up to R=17. New stellar proper motions were also determined with 2MASS and the USNO B1.0 catalog positions as first epoch. The catalog contains 2.24 million stars with proper motions, covering Pluto's sky path with 30 arcmin width. Its magnitude completeness is about R=18 with a limit about R=21. The catalog of star positions along Pluto's 2008-2015 sky path was built in the context of the investigation of Pluto and its satellites, aiming to support precise astrometric predictions for stellar occultations by Pluto, Charon, Hydra and Nix for the period 2008-2015. For that, we have carried out in 2007 an observational program at the ESO2p2/WFI instrument covering the sky path of Pluto from 2008 to 2015. We highlight the usefulness of this catalog as a reference frame for star/body astrometric follow-up before and after future stellar occultations involving the Pluto system. In this way, updates for the ephemeris offsets of these bodies and for the position of star candidates for occultations can be enhanced. Besides, the catalog also furnishes useful photometric information for field stars in the flux calibration of observed light curves. The prediction tables of stellar occultations by Pluto, Charon, Nix and Hydra for 2008-2015 were built for investigating the physical properties of Pluto and its satellites, for understanding in a broader sense transneptunian objects - keystones in the study of structure, origin and evolution of the Solar System. Our aim was to derive precise, astrometric predictions. We then constructed an astrometric star catalog in the UCAC2 system covering Pluto's sky path. For that, we have carried out in 2007 an observational program at the ESO2p2/WFI instrument covering the sky path of Pluto from 2008 to 2015. Based on the past 2005-8 occultations successfully predicted, recorded and fitted, a linear drift with time in declination with regard to DE418/plu017 ephemerides was determined for Pluto and used in the current predictions. For offset (mas)=A(t(yr)-2005.0)+B, we find A=+30.5+/-4.3mas/yr and B=-31.5+/-11.3mas, with standard deviation of 14.4mas for the offsets. For these past occultations, predictions and follow-up observations were made with the 0.6m and 1.6m telescopes at the Laboratorio Nacional de Astrofisica/Brazil. No ephemeris correction was applied for right ascension. Although an oscillation pattern related to an error in Pluto's heliocentric distance (geocentric parallax error) cannot be ruled out, none of the attempted models for this scenario could fit the more dispersed right ascension ephemeris offsets derived from the studied past occultations, at least not well below 50mas, in contrast with the standard deviation of only 14.4mas achieved for declination. The candidate stars listed in the prediction tables were searched using a proximity radius of 335mas with the geocentric apparent orbit (corrected by ephemeris offsets) of the body considered. This radius is about the apparent radius of Pluto (50mas) plus the apparent Earth radius (285mas) as projected in the sky plane at 31AU (Pluto-Earth distance for 2008-2015). No threshold in R magnitude was used in the search for candidates. Pluto is crossing interstellar clouds, so relatively faint R objects may turn out to be bright infrared stars, perfect targets for the SOFIA observatory and for ground-based instruments well equipped with H, J or K band detectors (H, J and K magnitudes are promptly available in the tables if the star belongs to the 2MASS). Besides, events may be also favored by slow shadow speeds of less than 20km/s. Also, no constraint on a geographic place was applied, as in principle SOFIA observations can be done from any sub-solar point on Earth. Events in daylight at sub-planet point were not excluded either, as they could yet be observable in the dark, right above the horizon, from places near the Earth terminator. We furnish here prediction tables for future and also for past stellar occultations covering the sky path by Pluto between 2008-2015. The importance of predictions for occultations still to come is obvious. But the predictions of past occultations are also useful for at least three reasons. First, they can be used by anyone as reference for ongoing fittings of light curves of recent past observed events. Second, they serve to derive ephemeris drifts by comparing expected and observed central instants and C/A values. Finally, they can be used as an external check for the accuracy and precision of our prediction tables. In a general sense, assuming a bulk error of 30mas for C/A from the estimated errors of the catalog star positions and from the errors of the derived ephemeris offsets, we can state that the shadow path uncertainties over Earth are on the order of less than 800km for the stellar occultation predictions of Pluto and Charon. Considering orbital issues and the smaller sizes of Nix and Hydra, the probability of success quoted for these two satellites are about 10-25%. This is not as high as hoped, but not despairingly small, especially if the event occurs above a dense, populated region in terms of astronomers, including amateurs.2010A&A...515A..32Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/515/A32CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/515/A32https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/515/A32http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/515/A32https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/515/A32https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/515/A32http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/515/A32GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/515/A32/charon (Prediction table of stellar occ. Charon 2008-2015)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/515/A32/charon?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/515/A32/charon?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/515/A32/charon?GETtext/xml+votable180.050000true269.0787175-17.1523938890.005555555555555556Cone search capability for table J/A+A/515/A32/catalog (Catalog of star positions: Pluto sky path 2008-2015)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/515/A32/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/515/A32/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/515/A32/catalog?GETtext/xml+votable180.050000true269.15232564-17.868707250.005555555555555556Cone search capability for table J/A+A/515/A32/pluto (Prediction table of stellar occ. Pluto 2008-2015)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/515/A32/pluto?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/515/A32/pluto?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/515/A32/pluto?GETtext/xml+votable180.050000true269.005696667-17.1499480560.005555555555555556Cone search capability for table J/A+A/515/A32/table1 (*The (RA, DE) ESO2p2/WFI mosaic centers for Pluto sky path from 2008 to 2015)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/515/A32/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/515/A32/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/515/A32/table1?GETtext/xml+votable180.050000true270.5-17.16670.005555555555555556Cone search capability for table J/A+A/515/A32/nix (Prediction table of stellar occ. Nix 2008-2015)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/515/A32/nix?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/515/A32/nix?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/515/A32/nix?GETtext/xml+votable180.050000true269.200278889-17.1552288890.005555555555555556Cone search capability for table J/A+A/515/A32/hydra (Prediction table of stellar occ. Hydra 2008-2015)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/515/A32/hydra?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/515/A32/hydra?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/515/A32/hydra?GETtext/xml+votable180.050000true269.059250833-17.1510486110.0055555555555555565/7247 7256 7269-7270 7275-7276 7361-7362 6/28983 29003 29006-29007 29028 29030 29032-29034 29071 29073 29075 29084 29086 29093-29095 29099 29112 29114 29441-29443 29452https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/515/A32?format=asciidefaultJ/A+A/515/A32/charonPrediction table of stellar occ. Charon 2008-2015recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpUTC instant at closest approachstime.epochnullableRAJ2000Right ascension (J2000) of star (1)pos.eq.ra;meta.maine_RAJ2000? Right ascension error at catalog mean epoch (7)masstat.error;pos.eq.raintnullableDEJ2000Declination (J2000) of star (1)pos.eq.dec;meta.maine_DEJ2000? Declination error at catalog mean epoch (7)masstat.error;pos.eq.decintnullableSepMinimum Separation at closest approach (CA)arcsecpos.angDistancefloatPAPosition angle (PA) at closest approach (2)degpos.posAngfloatVshadOccultation shadow velocity (3)km/sphys.veloc;pos.lunar.occultfloatDistApparent geocentric distance at occultationAUpos.distance;pos.geocentricfloatRmagNormalized apparent magnitude in R bandmagphot.mag;em.opt.RfloatJmag? Normalized apparent J magnitude (4)magphot.mag;em.IR.JfloatnullableHmag? Normalized apparent H magnitude (4)magphot.mag;em.IR.HfloatnullableKmag? Normalized apparent K magnitude (4)magphot.mag;em.IR.KfloatnullableLongLongitude of the sub-solar point at occultationdegpos.earth.lonfloatLSTLocal solar time at closest approachtime.epochoRARight ascension ephemeris offset correctionmaspos.eq.ra;arith.difffloatoDEDeclination ephemeris offset correctionmaspos.eq.dec;arith.difffloatCatCatalog cross-identification flag (6)meta.id;meta.datasetcharStarDetails from the star catalogs 2MASS (II/246), UCAC2 (I/289), UCAC3 (I/315), PPMXL (I/317)meta.ref.urlcharAmf[0/6] Astrometric multiplicity flag (G1)meta.codeintpmRA? Proper motion in Right Ascension (pmRA*cosDE) (8)mas/yrpos.pm;pos.eq.raintnullablepmDE? Proper motion in Declination (8)mas/yrpos.pm;pos.eq.decintnullableJ/A+A/515/A32/catalogCatalog of star positions: Pluto sky path 2008-2015recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension in decimal degrees (J2000) at mean epoch "Epoch"degpos.eq.ra;meta.mainindexede_RAJ2000? Right ascension error at mean epoch (1)masstat.error;pos.eq.raintnullableDEJ2000Declination in decimal degrees (J2000) at mean epoch "Epoch"degpos.eq.dec;meta.mainindexede_DEJ2000? Declination error at mean epoch (1)masstat.error;pos.eq.decintnullableEpochMean epoch of coordinates (JD)dtime.epochdoublepmRA? Proper motion in Right Ascension (pmRA*cosDE) (2)mas/yrpos.pm;pos.eq.raintnullablepmDE? Proper motion in Declination (2)mas/yrpos.pm;pos.eq.decintnullableRmagMagnitude (apparent) in R bandmagphot.mag;em.opt.RfloatJmag? Magnitude (apparent) in J band (3)magphot.mag;em.IR.JfloatnullableHmag? Magnitude (apparent) in H band (3)magphot.mag;em.IR.HfloatnullableKmag? Magnitude (apparent) in K band (3)magphot.mag;em.IR.KfloatnullableerxMeasured error in CCD frames (x) coordinatesmasstat.error;instr.detinteryMeasured error in CCD frames (y) coordinatesmasstat.error;instr.detintNoNumber of observations per positionmeta.numberintCat[129] Flag on catalog cross-identification (4)meta.id;meta.datasetcharStarDetails from the star catalogs 2MASS (II/246), UCAC2 (I/289), UCAC3 (I/315), PPMXL (I/317)meta.ref.urlcharAmf[0/6] Astrometric multiplicity flag (G1)meta.codeintJ/A+A/515/A32/plutoPrediction table of stellar occ. Pluto 2008-2015LSTLocal solar time at closest approachtime.epochrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpUTC instant at closest approachstime.epochnullableRAJ2000Right ascension (J2000) of star (1)pos.eq.ra;meta.maine_RAJ2000? Right ascension error at catalog mean epoch (7)masstat.error;pos.eq.raintnullableDEJ2000Declination (J2000) of star (1)pos.eq.dec;meta.maine_DEJ2000? Declination error at catalog mean epoch (7)masstat.error;pos.eq.decintnullableSepMinimum Separation at closest approach (CA)arcsecpos.angDistancefloatPAPosition angle (PA) at closest approach (2)degpos.posAngfloatVshadOccultation shadow velocity (3)km/sphys.veloc;pos.lunar.occultfloatDistApparent geocentric distance at occultationAUpos.distance;pos.geocentricfloatRmagNormalized apparent magnitude in R bandmagphot.mag;em.opt.RfloatJmag? Normalized apparent J magnitude (4)magphot.mag;em.IR.JfloatnullableHmag? Normalized apparent H magnitude (4)magphot.mag;em.IR.HfloatnullableKmag? Normalized apparent K magnitude (4)magphot.mag;em.IR.KfloatnullableLongLongitude of the sub-solar point at occultationdegpos.earth.lonfloatoRARight ascension ephemeris offset correctionmaspos.eq.ra;arith.difffloatoDEDeclination ephemeris offset correctionmaspos.eq.dec;arith.difffloatCatCatalog cross-identification flag (6)meta.id;meta.datasetcharStarDetails from the star catalogs 2MASS (II/246), UCAC2 (I/289), UCAC3 (I/315), PPMXL (I/317)meta.ref.urlcharAmf[0/6] Astrometric multiplicity flag (G1)meta.codeintpmRA? Proper motion in Right Ascension (pmRA*cosDE) (8)mas/yrpos.pm;pos.eq.raintnullablepmDE? Proper motion in Declination (8)mas/yrpos.pm;pos.eq.decintnullableJ/A+A/515/A32/table1*The (RA, DE) ESO2p2/WFI mosaic centers for Pluto sky path from 2008 to 2015recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintYearYearyrtimeintRAJ2000Mosaic center right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Mosaic center declination (J2000)pos.eq.dec;meta.mainJ/A+A/515/A32/nixPrediction table of stellar occ. Nix 2008-2015CatCatalog cross-identification flag (6)meta.id;meta.datasetcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpUTC instant at closest approachstime.epochnullableRAJ2000Right ascension (J2000) of star (1)pos.eq.ra;meta.maine_RAJ2000? Right ascension error at catalog mean epoch (7)masstat.error;pos.eq.raintnullableDEJ2000Declination (J2000) of star (1)pos.eq.dec;meta.maine_DEJ2000? Declination error at catalog mean epoch (7)masstat.error;pos.eq.decintnullableSepMinimum Separation at closest approach (CA)arcsecpos.angDistancefloatPAPosition angle (PA) at closest approach (2)degpos.posAngfloatVshadOccultation shadow velocity (3)km/sphys.veloc;pos.lunar.occultfloatDistApparent geocentric distance at occultationAUpos.distance;pos.geocentricfloatRmagNormalized apparent magnitude in R bandmagphot.mag;em.opt.RfloatJmag? Normalized apparent J magnitude (4)magphot.mag;em.IR.JfloatnullableHmag? Normalized apparent H magnitude (4)magphot.mag;em.IR.HfloatnullableKmag? Normalized apparent K magnitude (4)magphot.mag;em.IR.KfloatnullableLongLongitude of the sub-solar point at occultationdegpos.earth.lonfloatLSTLocal solar time at closest approachtime.epochoRARight ascension ephemeris offset correctionmaspos.eq.ra;arith.difffloatoDEDeclination ephemeris offset correctionmaspos.eq.dec;arith.difffloatStarDetails from the star catalogs 2MASS (II/246), UCAC2 (I/289), UCAC3 (I/315), PPMXL (I/317)meta.ref.urlcharAmf[0/6] Astrometric multiplicity flag (G1)meta.codeintpmRA? Proper motion in Right Ascension (pmRA*cosDE) (8)mas/yrpos.pm;pos.eq.raintnullablepmDE? Proper motion in Declination (8)mas/yrpos.pm;pos.eq.decintnullableJ/A+A/515/A32/hydraPrediction table of stellar occ. Hydra 2008-2015recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpUTC instant at closest approachstime.epochnullableRAJ2000Right ascension (J2000) of star (1)pos.eq.ra;meta.maine_RAJ2000? Right ascension error at catalog mean epoch (7)masstat.error;pos.eq.raintnullableDEJ2000Declination (J2000) of star (1)pos.eq.dec;meta.maine_DEJ2000? Declination error at catalog mean epoch (7)masstat.error;pos.eq.decintnullableSepMinimum Separation at closest approach (CA)arcsecpos.angDistancefloatPAPosition angle (PA) at closest approach (2)degpos.posAngfloatVshadOccultation shadow velocity (3)km/sphys.veloc;pos.lunar.occultfloatDistApparent geocentric distance at occultationAUpos.distance;pos.geocentricfloatRmagNormalized apparent magnitude in R bandmagphot.mag;em.opt.RfloatJmag? Normalized apparent J magnitude (4)magphot.mag;em.IR.JfloatnullableHmag? Normalized apparent H magnitude (4)magphot.mag;em.IR.HfloatnullableKmag? Normalized apparent K magnitude (4)magphot.mag;em.IR.KfloatnullableLongLongitude of the sub-solar point at occultationdegpos.earth.lonfloatLSTLocal solar time at closest approachtime.epochoRARight ascension ephemeris offset correctionmaspos.eq.ra;arith.difffloatoDEDeclination ephemeris offset correctionmaspos.eq.dec;arith.difffloatCatCatalog cross-identification flag (6)meta.id;meta.datasetcharStarDetails from the star catalogs 2MASS (II/246), UCAC2 (I/289), UCAC3 (I/315), PPMXL (I/317)meta.ref.urlcharAmf[0/6] Astrometric multiplicity flag (G1)meta.codeintpmRA? Proper motion in Right Ascension (pmRA*cosDE) (8)mas/yrpos.pm;pos.eq.raintnullablepmDE? Proper motion in Declination (8)mas/yrpos.pm;pos.eq.decintnullable