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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 nature of some doubtful open clusters as revealed by HIPPARCOS
We discuss the nature of some galactic open clusters by using propermotions and parallaxes from the Hipparcos and ACT catalogues. We showthat the clusters Collinder 399, Upgren 1, NGC 1252 and Melotte 227 donot exist. Collinder 132 is found to be mainly composed out of membersof an OB association, but there may be a star cluster present in thisarea too. Roeser & Bastian (1994) proposed that NGC 2451 consists oftwo star clusters. We show that NGC 2451 A definitively does exist, NGC2451 B may exist. A star cluster may also be present in the area ofRoslund 5. The Hipparcos data finally confirm the reality of Collinder135.
| Visual measurements of southern double stars. II
A group of 248 micrometric observations of 104 double stars arepresented, forming the second series of a program carried out at Cordobawith a 30 cm refractor. Usually neglected IDS pair south of -60 deg areselected for observation, most of them having been measured only one ortwo times previously. The measurements are compared with all the earlierobservations to derive estimates for the personal equation in P.A. andseparation, and the nature of many pairs is discussed by making use ofcatalog proper motions.
| The frequency analysis of low amplitude delta Scuti stars. V - HD 188520
The paper analyzes HD188520 which is an A7IV/V star shown to be a newdelta Scuti variable. Photometry of this star is consistent with theA7/IV/V spectral classification; a frequency analysis of 502observations of HD188520 in a 60.5 hr period on 10 nights is presented.Two frequencies are present throughout the 66 day time-span of the dataset, although the alias at 3.760/day may be the correct lower frequency.It is suggested that the frequency at 4.762/day may result from g-modepulsation or ellipsoidal variability.
| Radial and non-radial oscillations in the very high metallicity Delta Scuti star HD 188136
The paper analyzes observations which show that HD 188136 is a DeltaScuti star. The metallicity index and the Sr4077 line which is nearly asstrong as H(delta) show that this star has a very high metallicity.Frequency analysis of 173 hr observations obtained on 30 nights in1978-79 was made; three frequencies were present throughout the entiredata set, one of which is due to a nonradial mode. It is suggested thatsince the Delta Scuti star evolves off the main sequence, it passesthrough a stage where radial and nonradial modes of the same k-valuecoincide.
| Four-color photoelectric photometry of two high-latitude clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1968AJ.....73..556E&db_key=AST
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Sekizlik |
| Sað Açýklýk: | 20h04m00.69s |
| Yükselim: | -78°46'45.7" |
| Görünürdeki Parlaklýk: | 8.186 |
| Uzaklýk: | 188.679 parsek |
| özdevim Sað Açýklýk: | 3.6 |
| özdevim Yükselim: | -18 |
| B-T magnitude: | 8.366 |
| V-T magnitude: | 8.201 |
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