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Hα Spectroscopy of RW Monocerotis
Five years of sparse full-orbit Hα spectroscopy are presented forthe short-period Algol RW Monocerotis. A spectroscopic mass ratio isderived that confirms the published photometric mass ratio. Of the twopublished rotation rates of the primary star, 66 and 260 kms-1, the slower best fits our observations. Hα emissionwas not seen during any of five eclipses, indicating that the secondaryis notstrongly chromospherically active. At every epoch an emissionfeature between the two stars was found, confirming that there iscontinuous mass transfer. However, an accompanying accretion disk wasseen in only two of six observing runs, using out-of-eclipsespectroscopy. Comparing with models, we show how a single out-of-eclipseHα observation can provide information on the mass transferpresence at that epoch. Finally, we see redshifted absorption justbefore and after primary eclipse, consistent with the location andvelocity of a mass transfer stream. However, the Hα absorptionequivalent width (with respect to the out-of-eclipse continuum) fallsproportionally with the primary's visibility between first and secondcontact. This indicates that the stream is projected against the entireface of the primary, a much larger area than predicted by theory.
| A catalog of rotational and radial velocities for evolved stars
Rotational and radial velocities have been measured for about 2000evolved stars of luminosity classes IV, III, II and Ib covering thespectral region F, G and K. The survey was carried out with the CORAVELspectrometer. The precision for the radial velocities is better than0.30 km s-1, whereas for the rotational velocity measurementsthe uncertainties are typically 1.0 km s-1 for subgiants andgiants and 2.0 km s-1 for class II giants and Ib supergiants.These data will add constraints to studies of the rotational behaviourof evolved stars as well as solid informations concerning the presenceof external rotational brakes, tidal interactions in evolved binarysystems and on the link between rotation, chemical abundance and stellaractivity. In this paper we present the rotational velocity v sin i andthe mean radial velocity for the stars of luminosity classes IV, III andII. Based on observations collected at the Haute--Provence Observatory,Saint--Michel, France and at the European Southern Observatory, LaSilla, Chile. Table \ref{tab5} also available in electronic form at CDSvia anonymous 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.
| The rotational break for G giants
New high-resolution spectroscopic observations have been obtained for 73G giants. Fourier analysis of their spectral lines yields rotationvelocities and macroturbulence dispersions. Combined with data from anearlier study, total of 86 analyses of luminosity class III giants isnow available. The existence of a rotational discontinuity forluminosity class III giants is confirmed, but it is found to be near G0III rather than G5 III, as indicated in the earlier work. Evidence forrotation being a single-valued function of spectral type isstrengthened. The observations are interpreted in terms of adynamo-generated magnetic brake and a 'rotostat' phenomenon.
| Radial velocity study of the Be star Beta Tau (HR 1910)
Extensive radial velocity investigation has been presented in this paperfor the bright Be star HR 1910, based upon thirty-three spectrograms.The analysis of these radial velocity measurements has demonstratedclearly the binary nature of the star, and new orbital elements weredetermined. A brief discussion of the previous work on this systemappears in the relevant sections.
| Narrow-band photometry of late-type stars. II
This paper presents extensive narrow-band photometry in the Uppsalasystem supplementing earlier published mesurements so that data now areavailable for all late-type stars brighter than V = 6.05 and a number ofgalactic cluster members. Numerous UBV and BV measurements are alsopublished. The data are used to determine relations for the predictionof UBV intrinsic colors for late-type stars from the narrow-bandmeasurements. The main purpose of the data is to constitute the basisfor the determination of solar-neighborhood space densities of late-typestars, mainly giants of different kinds; these space densities will becombined with narrow-band data for fainter stars in the north Galacticpole region to yield the decrease of space density with distance fromthe galactic plane for many kinds of late-type stars.
| MK classification for F- and G-type stars. IV
MK spectral classifications are given for 112 stars brighter than mv =7.5, having HD types F2-G5. The classifications were made on slitspectrograms of dispersion 75 A/mm at H gamma.
| MK spectral types for some F and G stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1979PASP...91...83C&db_key=AST
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| Takýmyýldýz: | Zincirli Prenses |
| Sað Açýklýk: | 00h28m56.60s |
| Yükselim: | +36°54'00.0" |
| Görünürdeki Parlaklýk: | 6.26 |
| Uzaklýk: | 142.248 parsek |
| özdevim Sað Açýklýk: | -2.9 |
| özdevim Yükselim: | -3.6 |
| B-T magnitude: | 7.43 |
| V-T magnitude: | 6.375 |
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