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Ýlgili Makaleler
Discovery of a Second Nova Eruption of V2487 Ophiuchi
A directed search for previously undiscovered nova eruptions wasconducted in the astronomical plate archives at Harvard CollegeObservatory and Sonneberg Observatory. We found that an eruption ofV2487 Oph (Nova Oph 1998) occurred on 1900 June 20. V2487 Oph waspreviously classified as a classical nova, which we identified as aprobable recurrent nova based on its large expansion velocities and thepresence of high excitation lines in the outburst spectrum. The eventwas recorded on Harvard plate AM 505, at a B magnitude of 10.27 ±0.11, which is near the peak. The outburst can only be seen on oneplate, but the image has a characteristic dumbbell shape (caused by adouble exposure) that is identical to the other star images on theplate, and thus is not a plate defect. We conclude that this is in facta previously undiscovered nova outburst of V2487 Oph, confirming ourprediction that it is a recurrent nova. We also examine the discoveryefficiency for eruptions of the system and conclude that a randomlytimed outburst has, on average, a 30% chance of being discovered in thepast century. Using this, we deduce a recurrence time for V2487 Oph ofapproximately 18 years, which implies that the next eruption is expectedaround 2016.
| A catalog of far-ultraviolet point sources detected with the fast FAUST Telescope on ATLAS-1
We list the photometric measurements of point sources made by the FarUltraviolet Space Telescope (FAUST) when it flew on the ATLAS-1 spaceshuttle mission. The list contains 4698 Galactic and extragalacticobjects detected in 22 wide-field images of the sky. At the locationssurveyed, this catalog reaches a limiting magnitude approximately afactor of 10 fainter than the previous UV all-sky survey, TDl. Thecatalog limit is approximately 1 x 10-14 ergs A sq cm/s,although it is not complete to this level. We list for each object theposition, FUV flux, the error in flux, and where possible anidentification from catalogs of nearby stars and galaxies. Thesecatalogs include the Michigan HD (MHD) and HD, SAO, the HIPPARCOS InputCatalog, the Position and Proper Motion Catalog, the TD1 Catalog, theMcCook and Sion Catalog of white dwarfs, and the RC3 Catalog ofGalaxies. We identify 2239 FAUST sources with objects in the stellarcatalogs and 172 with galaxies in the RC3 catalog. We estimate thenumber of sources with incorrect identifications to be less than 2%.
| Interstellar reddening in the Southern Hemisphere. I - The UVBY beta observations
The uvby-beta photometric data obtained from a Southern Hemisphereobservational project is presented. A uvby-beta photometric network ofnearly 3900 A and early F stars has been established with the intentthat the stars serve as 'space probes' for measurements of interstellarreddening.
| Observations of double stars and new pairs. XIV
Results of a continuing survey of visual double stars are presented,including 4880 measurements made from February 1987 to November 1989.The positions in WDS format and Durchmusterung numbers are given for 194pairs first reported here. Micrometer measurements of 1142 doubles madewith the Swarthmore 61 cm refractor are presented. Magnitudes areestimated for some of the objects. Plate measurements, plateorientations, position angles, number of nights, and measured exposuresare given. Visual observations of 342 pairs obtained in May 1989 atCerro Tololo, mostly with the 1.0 m reflector, are reported.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Yilanci |
| Sað Açýklýk: | 17h34m09.18s |
| Yükselim: | -19°10'29.7" |
| Görünürdeki Parlaklýk: | 8.692 |
| Uzaklýk: | 256.41 parsek |
| özdevim Sað Açýklýk: | 20 |
| özdevim Yükselim: | -8.7 |
| B-T magnitude: | 9.253 |
| V-T magnitude: | 8.739 |
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