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Be stars in open clusters. II. Balmer line spectroscopy
We present Hα line profiles (R ~= 3x103, S/N ~=102 at continuum level, ~= 50 for some objects) for 58 starsin 8 northern open clusters and associations, complemented with Hβand Hγ profiles for 36 of them as well as Hdelta and Hepsilon for16 programme stars. Our observations, though lower in resolution, yieldresults which are in good agreement with those obtained in earlier worksbased mainly on field Be stars. Our data suggest a similar spectroscopicbehavior for both field and cluster Be stars. The line parameters (EW,FWHM, Delta vp) have been obtained for each line. Nearly thewhole set of stars have previously published quasi-simultaneousuvby\beta photometry, so a study of reliable correlations betweenphotometric and spectroscopic data can be undertaken. Based onobservations made at the German-Spanish Astronomical Center, Calar Alto,Spain which is operated by the Max Planck Institut fuer Astronomie,Heidelberg, jointly with the spanish National Commission for Astronomy.
| Be stars in open clusters I. uvbyβ photometry.
We present uvbyβ photometry for Be stars in eight open clusters andtwo OB associations. It is shown that Be stars occupy anomalouspositions in the photometric diagrams, which can be explained in termsof the circumstellar continuum radiation contribution to the photometricindices. In the (b-y)_0_-M_V_ plane Be stars appear redder than the nonemission B stars, due to the additional reddening caused by the hydrogenfree-bound and free-free recombination in the circumstellar envelope. Inthe c_0_-M_V_ plane the earlier Be stars present lower c_0_ values thanabsorption-line B stars, which is caused by emission in the Balmerdiscontinuity, while the later Be stars deviate towards higher c_0_values, indicating absorption in the Balmer discontinuity ofcircumstellar origin.
| Hα Interferometric Optical and Near Infrared Photometric Studies of Star Forming Regions - Part One - the Cepheus-B / SH:2-155 / CEPHEUS-OB3 Association Complex
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&A...273..619M&db_key=AST
| A photometric analysis of the Cepheus OB3 region
Results are presented on Stromgren-Crawford uvby-beta photometry carriedout at Calar Alto (Spain) for 45 stars in the Cepheus OB3 regioncovering an apparent area of 6 deg x 6 deg. The relationship of thesestars with the association is examined. Three of these stars (BD +62 deg2114, BD +62 deg 2152, and BD +62 deg 2156) are identified as members ofthis association, while two more (BD +64 deg 1714 and BD +64 deg 1717)are classified as possible members. It is noted that intrinsic colorsand absolute magnitudes of member stars are consistent with thehypothesis of Blaauw (1964) and Garmany (1973) of the existence of twosubgroups with different evolutionary phases.
| Internal motions in the association Cep OB3.
Abstract image available at:http://adsabs.harvard.edu/abs/1973AJ.....78..185G
| Spectral classification in the association III Cephei and the ratio of total-to-selective absorption.
Abstract image available at:http://adsabs.harvard.edu/abs/1970AJ.....75.1001G
| Photoelectric Photometry of the Association III Cephei.
Abstract image available at:http://adsabs.harvard.edu/abs/1959ApJ...130...69B
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| קבוצת-כוכבים: | קפיאוס |
| התרוממות ימנית: | 22h50m09.66s |
| סירוב: | +61°56'52.8" |
| גודל גלוי: | 9.269 |
| תנועה נכונה: | -13.3 |
| תנועה נכונה: | -9.2 |
| B-T magnitude: | 9.819 |
| V-T magnitude: | 9.315 |
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