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The long-period orbit of the dwarf nova V630 Cassiopeiae
We present extensive spectroscopy and photometry of the dwarf nova V630Cassiopeiae. A late-type (K4-5) absorption spectrum is easilydetectable, from which we derive the orbital parameters. We find aspectroscopic period of P=2.56387+/-4×10-5d and asemi-amplitude of K2=132.9+/-4.0kms-1. Theresulting mass function, which is a firm lower limit on the mass of thewhite dwarf, is then f(M)=0.624+/-0.056Msolar. The secondarystar is a `stripped giant' and, using relations between the core massand the luminosity and between the core mass and the radius, we derive alower limit of M2>=0.165Msolar for thesecondary star. The rotational velocity of the secondary star is notresolved in our spectra and we place a limit ofVrotsini<40kms-1. The long-term light curveshows variations of up to 0.4mag on short (1-5d) time-scales, andvariations of 0.2-0.4mag on longer (3-9 months) time-scales. In spite ofthese variations, the ellipsoidal light curve of the secondary star iseasily seen when the data are folded on the spectroscopic ephemeris.Ellipsoidal models fitted to the mean light curve give an inclination inthe range 66.96°<=i<=78.08° (90 per cent confidence). Thisinclination range, and the requirement thatM2>=0.165Msolar andVrotsini<40kms-1, yields a white dwarf mass ofM1=0.977-0.098+0.168Msolar and a secondary starmass of M2=0.172-0.012+0.029Msolar (90 per centconfidence limits). Our findings confirm the suggestion of Warner thatV630 Cas is a rare example of a dwarf nova with a long orbital period.
| 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.
| 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.
| The UBV Observations of Possible Protoplanetary V1027-CYGNI in 1991
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| Interstellar extinction in Cygnus between the Orion and Sagittarius spiral arms
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| La mesure des vitesses radiales au prisme objectif. XIII. 6ème liste de vitesses radiales déterminées au prisme objectif à vision directe
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| Reddened Early m- and S-Type Stars in Two Galactic Zones.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1957ApJ...125..408B&db_key=AST
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Observation and Astrometry data
| Constellation: | Cygnus |
| Right ascension: | 20h03m24.10s |
| Declination: | +29°57'28.2" |
| Apparent magnitude: | 8.198 |
| Distance: | 316.456 parsecs |
| Proper motion RA: | 13.1 |
| Proper motion Dec: | -0.4 |
| B-T magnitude: | 10.056 |
| V-T magnitude: | 8.352 |
Catalogs and designations:
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