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Hipparcos red stars in the HpV_T2 and V I_C systems
For Hipparcos M, S, and C spectral type stars, we provide calibratedinstantaneous (epoch) Cousins V - I color indices using newly derivedHpV_T2 photometry. Three new sets of ground-based Cousins V I data havebeen obtained for more than 170 carbon and red M giants. These datasetsin combination with the published sources of V I photometry served toobtain the calibration curves linking Hipparcos/Tycho Hp-V_T2 with theCousins V - I index. In total, 321 carbon stars and 4464 M- and S-typestars have new V - I indices. The standard error of the mean V - I isabout 0.1 mag or better down to Hp~9 although it deteriorates rapidly atfainter magnitudes. These V - I indices can be used to verify thepublished Hipparcos V - I color indices. Thus, we have identified ahandful of new cases where, instead of the real target, a random fieldstar has been observed. A considerable fraction of the DMSA/C and DMSA/Vsolutions for red stars appear not to be warranted. Most likely suchspurious solutions may originate from usage of a heavily biased color inthe astrometric processing.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997).}\fnmsep\thanks{Table 7 is onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/397/997
| 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
| HIPPARCOS data for two open clusters containing cepheids
Using proper motion data from the Hipparcos satellite it is shown thatthe cepheids S Nor and U Sgr are members of the open clusters NGC 6087and M 25, respectively. The precision of the Hipparcos data is needed toconclusively carry out a membership test. Parallax data, also obtainedfrom Hipparcos, do not contradict the proper motion results.
| A catalogue of [Fe/H] determinations: 1996 edition
A fifth Edition of the Catalogue of [Fe/H] determinations is presentedherewith. It contains 5946 determinations for 3247 stars, including 751stars in 84 associations, clusters or galaxies. The literature iscomplete up to December 1995. The 700 bibliographical referencescorrespond to [Fe/H] determinations obtained from high resolutionspectroscopic observations and detailed analyses, most of them carriedout with the help of model-atmospheres. The Catalogue is made up ofthree formatted files: File 1: field stars, File 2: stars in galacticassociations and clusters, and stars in SMC, LMC, M33, File 3: numberedlist of bibliographical references The three files are only available inelectronic form at the Centre de Donnees Stellaires in Strasbourg, viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5), or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| 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.
| Open cluster chemical composition. 1: Later type stars in eight clusters
Abundance analyses of 36 stars associated with eight open clusters (IC2581, NGC 3532, NGC 5822, NGC 6067, NGC 6087, IC 4725 (M25), IC 4756,and NGC 6882/6885) are presented. The stars are primarily evolved G andK giants and supergiants. Cepheids in NGC 6067, NGC 6087, and IC 4725are included as are non-cluster Cepheids near the clusters NGC 3532, NGC6067, and IC 4725. With the addition of a background K giant in IC 4725,the total number of stars is 40. Elemental abundances derived includeLi, C, N, O, the alpha-elements, the Fe peak, and limited data on theheavy elements. The Na abundances of the sample show a gravitydependence in the sense of an increase in the abundance as the gravitydecreases. The CNO abundances indicate that these objects are processed(on the whole), and that they show the O deficiency previously noted inintermediate mass stars by Luck & Lambert (1981, 1985). There arefour stars in the sample which appear to be unprocessed: two giants andtwo supergiants. There are also two super-Li stars in the sample, one ofwhich is most likely a weak G-band star. It is suggested that thesuper-Li F supergiants could be evolved blue stragglers. The moststriking result of the study is the finding that the (O/Na) ratiocorrelates strongly with the gravity and the stellar mass, thus implyingthat there is a nonstandard additional mixing process affecting thesurface abundances of these stars. A promising candidate for the mixingprocess is the turbulent diffusive mixing process proposed byDenissenkov (1993) which brings Na to the surface and which could alsolead to a modification of the oxygen content.
| Membership of Cepheids and red giants in 8 open clusters - NGC 129, 6067, 6087, 6649, 6664, IC 4725, LY 6, RU 79
The membership of eight cluster Cepheids,DL Cas,EV Sct, V367 Sct, S Nor,TW Nor,V340 Nor, U Sgr and CS Vel, has been examined by comparing theirsystemic radial velocity with that observed for the red giants in thesame clusters. The membership is very probable in seven cases, theonly-exception being CS Vel. Additional observations of main sequencestars are necessary to confirm some of the conclusions. Onespectroscopic binary was discovered among the Cepheids (DL Cas) and atleast four were among the red giants. Orbits have been determined fortwo red giants, one in NGC 129 and one in IC 4725. The position withinthe instability strip of the nonvariable F5Ib star in NGC 129 is due toits probable composite (gK + dB) character. The ratio of the number ofCepheids to the number of red giants is less than 1, in good agreementwith the prediction of evolutionary models with core overshooting. Thisstudy is based on 382 observations of 45 stars, obtained with the radialvelocity scanner CORAVEL.
| The Galactic Cluster NGC 6087.
Abstract image available at:http://adsabs.harvard.edu/abs/1964ApJS....8..329L
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Osservazione e dati astrometrici
| Costellazione: | Regolo |
| Ascensione retta: | 16h19m17.09s |
| Declinazione: | -58°05'28.8" |
| Magnitudine apparente: | 7.647 |
| Distanza: | 900.901 parsec |
| Moto proprio RA: | 4.1 |
| Moto proprio Dec: | 11.4 |
| B-T magnitude: | 9.995 |
| V-T magnitude: | 7.841 |
Cataloghi e designazioni:
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