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Photoelectric Minimum Times of Some Eclipsing Binary Stars
We present 20 minima times of 8 eclipsing binaries.
| Up-to-date UBV light and O-C curves analyses of the eclipsing binary V477 Cygni
New and complete UBV light curves and times of minimum are presented forthe Algol-type eclipsing binary V477 Cygni (Sp. A3 V+F5 V, mv=8.5, P=2.347 days). The binary orbit of the system is highly eccentricand the system shows an apsidal motion. Using the Wilson-Devinneymethod, two photometric models, without (MODEL A) and with (MODEL B)third-body light contribution to the total light of the system, areobtained. Period analysis also gives some slender evidence for theunseen third-body in the system with the orbital period of about 157years. In the MODEL A approximation the apsidal motion period isobtained to be 371 years while it is about 434 years in the MODEL Bapproximation. The photometric mass ratio (q ~ 0.75) is in goodagreement with the spectroscopic value given by Popper(\cite{Popper1968}). The masses we obtained are 1.80+/-0.10Msun and 1.35+/-0.08 Msun and the radii are1.60+/-0.03 Rsun and 1.42+/-0.03 Rsun for theprimary and secondary components, respectively. Absolute dimensions havebeen compared with the models using a moderate amount of convectiveovershooting and mass loss given by Claret & Giménez(\cite{Claret1991}). In the log M - log R diagram both components arelocated above but close to the ZAMS. It is possible to say from the logTe - log L diagram that the secondary component is justcoming to the main sequence while the primary is slightly evolved fromthe ZAMS. The theoretical evolutionary models give an age of6.4*E8 yrs for the system.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.73.128.5) or via http:/ /cdsweb.u-strasbg.fr /cgi-bin/qcat?J/A+A/409/959
| Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
We complete construction of a catalog containing improved astrometry andnew optical/infrared photometry for the vast majority of NLTT starslying in the overlap of regions covered by POSS I and by the secondincremental Two Micron All Sky Survey (2MASS) release, approximately 44%of the sky. The epoch 2000 positions are typically accurate to 130 mas,the proper motions to 5.5 mas yr-1, and the V-J colors to0.25 mag. Relative proper motions of binary components are measured to 3mas yr-1. The false-identification rate is ~1% for11<~V<~18 and substantially less at brighter magnitudes. Theseimprovements permit the construction of a reduced proper-motion diagramthat, for the first time, allows one to classify NLTT stars intomain-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We inturn use this diagram to analyze the properties of both our catalog andthe NLTT catalog on which it is based. In sharp contrast to popularbelief, we find that NLTT incompleteness in the plane is almostcompletely concentrated in MS stars, and that SDs and WDs are detectedalmost uniformly over the sky δ>-33deg. Our catalogwill therefore provide a powerful tool to probe these populationsstatistically, as well as to reliably identify individual SDs and WDs.
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| New Observed Times of Minima for MR Cyg, V477 Cyg
Not Available
| Objective-prism discoveries in the northern sky - II.
Five tables list the observed characteristics of 244 northern hemispherestars recorded in 100 108 A/mm dispersion plates at H-gamma wavelengths.The 5 x 5 deg fields contained a number of suspected weak-metal objects.Listings are divided into peculiar A stars, metallic line and deltaDelphini stars, high luminosity objects, Ca II emission stars of the Gand K type, and composite spectra.
| Spectral types for proper motion stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975AJ.....80..239B&db_key=AST
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Dades d'Observació i Astrometria
| Constel·lació: | Cygnus |
| Ascensió Recta: | 20h04m46.65s |
| Declinació: | +32°02'29.9" |
| Magnitud Aparent: | 8.926 |
| Distancia: | 90.827 parsecs |
| Moviment propi RA: | 192.2 |
| Moviment propi Dec: | -63.8 |
| B-T magnitude: | 9.575 |
| V-T magnitude: | 8.98 |
Catàlegs i designacions:
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