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CCD astrometry and components instrumental magnitude difference of 432 Hipparcos wide visual double stars
Context: We measured the angular separations, position angles, ΔV, Δ y and Δ I of wide visual double stars during the period2003-2005. At least one component of the double stars in our sample hasan entry in the Hipparcos catalogue. Aims: Our measurements are acontribution to the study of the nature of these double stars. Methods: The northern double stars of the project were observed with the1.2 m telescope of the Kryonerion observatory and the southern with the1.0 m SAAO. We performed multiple-exposure CCD imaging of our targetsand used the standard procedure of data reduction and astrometric CCDcalibrations. Results: We present measurements of 213 northern and 219southern wide binaries.Based on observations made at Kryonerion Observatory of the NationalObservatory of Athens, Greece, and the South African AstronomicalObservatory. Full Table 1 and Tables 2, 3 are only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/472/1055
| Two Active Nuclei in 3C 294
The z=1.786 radio galaxy 3C 294 lies < 10" from a 12 mag star and hasbeen the target of at least three previous investigations using adaptiveoptics (AO) imaging. A major problem in interpreting these results isthe uncertainty in the precise alignment of the radio structure with theH- or K-band AO imaging. Here we report observations of the position ofthe AO guide star with the Hubble Space Telescope Fine Guidance Sensor,which, together with positions from the second United States NavalObservatory's CCD Astrograph Catalog (UCAC2), allow us to register theinfrared and radio frames to an accuracy of better than 0.1". The resultis that the nuclear compact radio source is not coincident with thebrightest discrete object in the AO image, an essentially unresolvedsource on the eastern side of the light distribution, as Quirrenbach andcoworkers had suggested. Instead, the radio source is centered about0.9" to the west of this object, on one of the two apparently real peaksin a region of diffuse emission. Nevertheless, the conclusion ofQuirrenbach and coworkers that 3C 294 involves an ongoing merger appearsto be correct: analysis of a recent deep Chandra image of 3C 294obtained from the archive shows that the nucleus comprises two X-raysources, which are coincident with the radio nucleus and the easternstellar object. The X-ray/optical flux ratio of the latter makes itextremely unlikely that it is a foreground Galactic star.Based in part on observations made with the NASA/ESA Hubble SpaceTelescope, obtained at the Space Telescope Science Institute, which isoperated by the Association of Universities for Research in Astronomy(AURA), Inc., under NASA contract NAS5-26555. These observations areassociated with proposal 08315. Based in part on data collected atSubaru Telescope, which is operated by the National AstronomicalObservatory of Japan. Some of the data presented herein were obtained atthe W. M. Keck Observatory, which is operated as a scientificpartnership among the California Institute of Technology, the Universityof California and the National Aeronautics and Space Administration. TheObservatory was made possible by the generous financial support of theW. M. Keck Foundation. Some of the data were also obtained from theChandra Data Archive, part of the Chandra X-Ray Observatory ScienceCenter, which is operated for NASA by the Smithsonian AstrophysicalObservatory.
| Common proper motion stars in the AGK 3
A search was made of common-proper-motion (CPM) systems among AGK 3stars. The selection of physical systems was based upon the ratiobetween the angular separation (rho) and the proper motion (mu); the CPMstars found are presented in two tables. Table I lists systems withrho/mu less than 1000 years. It contains 326 entries, and the proportionof optical pairs is estimated to be 1 percent. Table II lists systemswith rho/mu in the range 1000 to 3500 years; it contains 113 systems,but only 60 percent of them are physical. Nevertheless, these systemsoften have separations larger than 10,000 AU and are the mostinteresting for the study of the tail of the distribution function ofthe semimajor axes.
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Osservazione e dati astrometrici
| Costellazione: | Vergine |
| Ascensione retta: | 13h02m07.17s |
| Declinazione: | +07°16'51.7" |
| Magnitudine apparente: | 10.278 |
| Moto proprio RA: | -123 |
| Moto proprio Dec: | 16.6 |
| B-T magnitude: | 11.259 |
| V-T magnitude: | 10.359 |
Cataloghi e designazioni:
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