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Wide-field Survey of Emission-line Stars in IC 1396
We have made an extensive survey of emission-line stars in the IC 1396 HII region to investigate the low-mass population of pre-main-sequence(PMS) stars. A total of 639 H? emission-line stars were detectedin an area of 4.2 deg2 and their i' photometry was measured.Their spatial distribution exhibits several aggregates near the elephanttrunk globule (Rim A) and bright-rimmed clouds at the edge of the H IIregion (Rim B and SFO 37, 38, 39, 41), and near HD 206267, which is themain exciting star of the H II region. Based on the extinction estimatedfrom the near-infrared color-color diagram, we have selected PMS starcandidates associated with IC 1396. The age and mass were derived fromthe extinction-corrected color-magnitude diagram and theoretical PMStracks. Most of our PMS candidates have ages of <3 Myr and masses of0.2-0.6 M &sun;. Although it appears that only a few starswere formed in the last 1 Myr in the east region of the exciting star,the age difference among subregions in our surveyed area is not clearfrom the statistical test. Our results may suggest that massive starswere born after the continuous formation of low-mass stars for 10 Myr.The birth of the exciting star could be the late stage of slow butcontiguous star formation in the natal molecular cloud. It may havetriggered the formation of many low-mass stars at the denseinhomogeneity in and around the H II region by a radiation-drivenimplosion.
| 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
| 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.
| Catalogue of stars in the northern Milky Way having H-alpha in emission
Not Available
| 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.
| Solar-type stars in Cepheus OB 2 - H-alpha emission stars and IRAS point sources
Results are presented on a second-epoch survey for the H-alpha emissionstars and IRAS point sources in the field of Cepheus OB 2. The colormagnitude and color-color diagrams based on B, V, R, and I magnitudesshow that these stars are most likely the F-G type (with masses between1.5 solar mass and 3 solar masses), partly pre-Main-Sequence members ofCep OB 2; few of these stars might be distant red giants. Young embeddedobjects were found in the dark clouds around the H II region, which wereprobably formed due to the effects of the O-type star on the nearbyclouds.
| Photometry of the young open cluster Trumpler 37
Photoelectric UBV observations of 120 stars in the young open clusterTrumpler 37 are presented, primarily in the magnitude range 10.0 - 13.5.An analysis of the color-magnitude diagram of the cluster yields an ageof 6.7 million yr and reveals the presence of a number of possiblepre-main-sequence stars in the cluster.
| 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
| Determination of size, color indices, and spectral classes of stars in an area centered on R.A.=21h24m, Dec=+58.5deg.
Not Available
| Additional Stars whose Spectra have a Bright H α Line.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1950ApJ...112...72M&db_key=AST
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Miembro de los siguientes grupos:
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Datos observacionales y astrométricos
| Constelación: | Cefeo |
| Ascensión Recta: | 21h39m14.08s |
| Declinación: | +57°48'04.8" |
| Magnitud Aparente: | 10.13 |
| Movimiento Propio en Ascensión Recta: | -0.4 |
| Movimiento Propio en Declinación: | 0.5 |
| B-T magnitude: | 10.383 |
| V-T magnitude: | 10.151 |
Catálogos y designaciones:
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