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Interstellar Extinction Law in the Vicinity of the North America and Pelican Nebulae
The interstellar reddening law is derived for 15 heavily reddened starsin the area which includes the North America and Pelican nebulae and thedark cloud between them. The method is based on photometry of thesestars in the Vilnius seven-color system and on their MK spectral types.The mean law in this area is very similar to the law for a much widerarea in Cygnus derived earlier by other authors. It differs from thenormal law by exhibiting somewhat stronger extinction in the violet andthe near ultraviolet spectral region, i.e., it shows a smaller ``knee"in the blue part of the spectrum.
| Infrared and submillimetre studies of Vega-excess stars
We report new infrared and submillimetre observations of a sample of 24candidate Vega-excess stars, and derive CO masses, dust masses, gas todust ratios and the strengths of various emission lines. Most of thesestars have dustier discs than the class archetypes (Vega, Fomalhaut,beta Pic, etc.), yet, like the archetypes, all the stars observed in COshow the gas content of their discs to be depleted compared withmolecular cloud values. We discuss how the extra dust content mightimply that these stars are less evolved than the archetypes, and useother infrared and submillimetre characteristics to support thiscontention.
| UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
| Kinematic signatures of violent formation of galactic OB associations from HIPPARCOS measurements
Proper motions measured by Hipparcos confirm the large anomalousvelocities of the OB associations located around the Cygnus Superbubble(Cygnus OB1, OB3, OB7, and OB9), and reveal a clearly organizedexpanding pattern in Canis Major OB1. At the distances of theseassociations, the organized velocity patterns imply LSR velocities of upto ~ 60 km s(-1) for the associations in Cygnus, and about ~ 15 km s(-1)in Canis Major OB1. The magnitude and spatial arrangement of theexpanding motions suggests that very energetic phenomena are responsiblefor the formation of the present OB associations. This is independentlysupported by observations of the associated interstellar medium carriedout in other wavelengths. The gravitational instability scenarioproposed by Comeron & Torra 1994 (ApJ 423, 652) to account for theformation of the stars in the Cygnus Superbubble region is reviewed inthe light of the new kinematic data. It is found that the energeticrequirements set by the highest velocities on the OB associationpowering the Superbubble, Cygnus OB2, are too large by orders ofmagnitude. However, the scenario can still account for the formation ofmost of the stars if, as can be reasonably expected, the stars with thehighest measured velocities are actually runaways from Cygnus OB2itself. As for Canis Major OB1, we consider their formation in asupernova remnant, as suggested by Herbst & Assousa 1977 (ApJ, 217,473). The detection of a new runaway star, HIC 35707 (=HD 57682), whosemotion is directed away from the derived center of expansion, supportsthis scenario and provides an independent age for the supernova remnant,assuming that the runaway star was the binary companion of thesupernova. Based on a number of arguments, however, we find it unlikelythat the stars are a direct consequence of instabilities in theexpanding shell. We propose instead that their formation was triggeredin preexisting clouds, accelerated and compressed by the supernovaexplosion.
| 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.
| SAO stars with infrared excess in the IRAS Point Source Catalog
We have undertaken a search for SAO stars with infrared excess in theIRAS Point Source Catalog. In contrast to previous searches, the entireIRAS (12)-(25)-(60) color-color diagram was used. This selection yieldeda sample of 462 stars, of which a significant number are stars withcircumstellar material. The stars selected can be identified aspre-main-sequence stars, Be stars, protoplanetary systems, post-AGBstars, etc. A number of objects are (visual) binary stars.Characteristic temperatures and IR excesses are calculated and theirrelations to spectral type are investigated.
| Photoelectric photometry of OB stars in the Vilnius system
Not Available
| Photoelectric Photometry of Stars in the Vilnius System in the Area of the North America and Pelican Nebulae
Not Available
| The interstellar 217 NM band - A third catalogue of equivalent widths
A catalog of equivalent widths of the 217 nm interstellar absorptionband as well as other parameters characterizing the extinction curve inthe ultraviolet has been compiled for 790 O and B stars. A relativelytight correlation between the equivalent width of the 217 nm band andE(B-V) indicates that the absorber of this band is connected with thepopulation of larger interstellar grains responsible for the visualextinction. The parameter characterizing the amount of extinction in thefar UV is only weakly correlated with E(B-V), a result in accord withthe assumption that a second population of very small grains causes therapid increase of the far-UV extinction.
| Catalog of O-B stars observed with Tokyo Meridian Circle
A catalog of the O-B stars, selected from 'Blaauw-Parenago' list andRubin's catalog, has been compiled on the FK4 system by the observationsmade with Gautier 8-inch Meridian Circle at the Tokyo AstronomicalObservatory during the period, 1971 to 1979. It contains 1059 stars andwas compiled for the future establishment of high precision propermotions of O-B stars.
| A catalog of ultraviolet interstellar extinction excesses for 1415 stars
Ultraviolet interstellar extinction excesses are presented for 1415stars with spectral types B7 and earlier. The excesses with respect to Vare derived from Astronomical Netherlands Satellite (ANS) 5-channel UVphotometry at central wavelengths of approximately 1550, 1800, 2500, and3300 A. A measure of the excess extinction in the 2200-A extinction bumpis also given. The data are valuable for investigating the systematicsof peculiar interstellar extinction and for studying the character of UVinterstellar extinction in the general direction of stars for which theextinction-curve shape is unknown.
| The S201 far-ultraviolet imaging survey. II - A field in Cygnus
Far-ultraviolet imagery of a region in Cygnus, a 20 deg diameter fieldcentered near (1950) R. A. 21 h 31.2 m decl. +37 deg 25 arcmin, wasobtained by the S201 far-ultraviolet camera during the Apollo 16mission. In a 10 minute exposure covering the 1250-1600 A wavelengthrange (effective wavelength 1400 A), 730 star images can be detected,corresponding to a limiting ultraviolet magnitude of about m (1400) =10. Assuming nominal interstellar extinction values in this region nearthe galactic plane, this result corresponds to the detection of A0 Vstars to a distance of 300 pc and of B0 V stars to 1500 pc.Uncertainties in spectral classification and interstellar extinction forindividual objects are probably more significant than calibration ormeasurement errors. Most of the objects detected are identified withstars in the Smithsonian Astrophysical Observatory Star Catalog (1966),or the Catalog of Stellar Identifications (1979) or both, but 87 objectsremain unidentified (or are identified with late-type stars).
| UBV photometry of 180 early-type stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974PASP...86..795G&db_key=AST
| Spectral Classifications of 239 Early-Type Stars
Not Available
| Troisième catalogue de l'Observatoire de Besançon comprenant 764 étoiles réduites à 1950, 0 sans mouvement propre et 326 étoiles FK3 pour l'époque moyenne d'observation
Not Available
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Observation and Astrometry data
| Constellation: | Schwan |
| Right ascension: | 20h52m53.20s |
| Declination: | +42°36'27.9" |
| Apparent magnitude: | 8.449 |
| Distance: | 520.833 parsecs |
| Proper motion RA: | -2.3 |
| Proper motion Dec: | -4.1 |
| B-T magnitude: | 9.052 |
| V-T magnitude: | 8.499 |
Catalogs and designations:
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INHABITED SKY
