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Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| Catalogue of H-alpha emission stars in the Northern Milky Way
The ``Catalogue of Stars in the Northern Milky Way Having H-alpha inEmission" appears in Abhandlungen aus der Hamburger Sternwarte, Band XIin the year 1997. It contains 4174 stars, range {32degr <= l() II< 214degr , -10degr < b() II < +10degr } having the Hαline in emission. HBH stars and stars of further 99 lists taken from theliterature till the end of 1994 were included in the catalogue. We givethe cross-identification of stars from all lists used. The catalogue isalso available in the Centre de Données, Strasbourg ftp130.79.128.5 or http://cdsweb.u-strasbg.fr and at the HamburgObservatory via internet.
| Origin and Evolution of the Cepheus Bubble
We have imaged a 10 deg x 10 deg region of the Cepheus bubble in the J =1-0 line of CO and the 21 cm line of atomic hydrogen. The CO emissiondefines a giant expanding shell 120 pc in diameter, which is similar tothat seen in the IRAS sky maps. We estimate the total gas mass in theregion to be ~4 x 10^5 M_ȯ. The total kinetic energy from theobserved spread of velocities of the molecular clouds is ~10^51 ergs. Wesuggest that the members of earlier generations of massive stars in NGC7160 are responsible for the origin of the Cepheus bubble. These starscreated an expanding compressed shell of gas that became gravitationallyunstable at an age of ~7 Myr. The members of the Cepheus OB2 associationcomprise the second, intermediate generation of stars in this regionthat formed as a consequence of this instability. The numerous colorselected IRAS point sources represent the third and youngest generationof stars in this region. Our observations suggest the great importanceof sequentially triggered star formation in the region of the Cepheusbubble.
| Catalogue of stars in the northern Milky Way having H-alpha in emission
Not Available
| The structure of the IC1396 region.
We have made an extensive study of the molecular clouds associated withthe Hii region IC1396 in the rotational transitions J=1-0 and J=2-1 of^12^CO and ^13^CO and J=3-2 of ^12^CO with an average spatial resolutionof 2.5' and an average sampling of about 2.0', in order to getinformation on its structure and evolution. On the basis of ourobservations, which cover an area of more than 6deg^2^, we can classifythe molecular clouds into those directly associated with the ionizingO6.5V star HD 206267, producing the bright-rimmed clouds, and the coldgas along the line of sight, which is mainly foreground material. Thebright-rimmed clouds show the presence of warmer molecular gas throughhigher ^12^CO (2-1)/(1-0), ^13^CO (2-1)/(1-0) and ^12^CO (3-2)/(2-1)line ratios than the cold foreground gas. The warm clouds form roughly ashell-like arrangement with a diameter of 25 to 40pc around HD206267(though most are slightly closer to the Sun than the O star), and theyseem to be the remainder of the now dispersing molecular cloud whichgave birth to the O6.5 star and the star cluster Tr37 associated withit. All bright-rimmed clouds show internal structure on all size scales,including bipolar outflows. Optical, FIR (IRAS 12 to 100μm) and COmaps are in close agreement over the whole region, especially for thebright-rimmed clouds: Exceptions are some optically bright (ionized)regions, which show FIR, but no CO emission, and the cold foregroundclouds, which are very weak at FIR wavelengths. The entire mass of themapped IC1396 region is estimated to be 12000Msun_, which iscomposed of molecular (4000Msun_), atomic(5000Msun_), and ionized material (3000Msun_) innearly equal amounts. The masses of the bright-rimmed clouds range froma few to several 100Msun_.
| Photografic Research of Variable Stars in the Rgion of Association T2 Cephei
Results of the variability search among emission line stars andsuspected variables in the association T2 Cephei are given. Blinking ofthe association region plates obtained from 1968 till 1984 did not showany new variables. The variability of four previously suspectedvariables NSV 13756, 138802, 13897, and 14008 is confirmed. The period5.77d and CW type were determined for NSV 14008.
| Galactic OB associations in the northern Milky Way Galaxy. I - Longitudes 55 deg to 150 deg
The literature on all OB associations was reviewed, and their IRAS pointsource content was studied, between galactic longitude 55 and 150 deg.Only one third of the 24 associations listed by Ruprecht et al. (1981)have been the subject of individual studies designed to identify thebrightest stars. Distances to all of these were recomputed using themethod of cluster fitting of the B main sequence stars, which makes itpoossible to reexamine the absolute magnitude calibration of the Ostars, as well as for the red supergiant candidate stars. Also examinedwas the composite HR diagram for these associations. Associations withthe best defined main sequences, which also tend to contain very youngclusters, referred to here as OB clusters, have extremely few evolved Band A or red supergiants. Associations with poorly defined mainsequences and few OB clusters have many more evolved stars. They alsoshow an effect in the upper HR diagram referred to as a ledge byFitzpatrick and Garmany (1990) in similar data for the Large MagellanicCloud. It is suggested that the differences in the associations are notjust observational selection effects but represent real differences inage and formation history.
| Some characteristics of the young open cluster Trumpler 37.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976PASP...88..865G&db_key=AST
| A Spectroscopic and Photometric Investigation of the Association Cepheus OB2
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1968ApJ...154..923S&db_key=AST
| Spectroscopic absolute magnitudes of 571 B stars.
Not Available
| Equivalent widths and halfwidths of the lambda 4388 and lambda 4471 HeI lines, rotational velocities and lambda 4430 central depths for 450O to B5 stars.
Not Available
| Determination of size, color indices, and spectral classes of stars in an area centered on R.A.=21h24m, Dec=+58.5deg.
Not Available
| Second Supplement to the Mount Wilson Catalogue and Bibliography of Stars of Classes B and a whose Spectra have Bright Hydrogen Lines.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1949ApJ...110..387M&db_key=AST
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