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Diffraction-limited speckle interferometry and modeling of the circumstellar envelope of R CrB at maximum and minimum light
We present the first speckle interferometric observations of RCrB, the prototype of a class of peculiar stars which undergoirregular declines in their visible light curves. The observations werecarried out with the 6 m telescope at the Special AstrophysicalObservatory near maximum light (V=7, 1996 Oct. 1) and at minimum light(V=10.61, 1999 Sep. 28). A spatial resolution of 75 mas was achieved inthe K-band. The dust shell around R CrB is partially resolved, and thevisibility is approximately 0.8 at a spatial frequency of 10cycles/arcsec. The two-dimensional power spectra obtained at both epochsdo not show any significant deviation from circular symmetry. Thevisibility function and spectral energy distribution obtained nearmaximum light can be simultaneously fitted with a model consisting ofthe central star and an optically thin dust shell with densityproportional to r-2. The inner boundary of the shell is foundto be 82 Rstar (19 mas) with a temperature of 920 K.However, this simple model fails to simultaneously reproduce thevisibility and spectral energy distribution obtained at minimum light.We show that this discrepancy can be attributed to thermal emission froma newly formed dust cloud.
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| Accuracy of two-dimensional spectral classes derived through DDO photometry.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977AJ.....82..832Y&db_key=AST
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| Takýmyýldýz: | Kuzey Taci |
| Sað Açýklýk: | 15h52m21.51s |
| Yükselim: | +28°36'26.6" |
| Görünürdeki Parlaklýk: | 7.921 |
| Uzaklýk: | 174.216 parsek |
| özdevim Sað Açýklýk: | -11.1 |
| özdevim Yükselim: | 22.8 |
| B-T magnitude: | 9.537 |
| V-T magnitude: | 8.055 |
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