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A critical test of stellar evolution and convective core `overshooting' by means of zeta Aurigae systems
Quantitative tests of late stellar evolution are presented by computingmodels with our evolutionary code to match the exact properties ofcertain zeta Aurigae eclipsing binaries and related non-eclipsingsystems. Those binaries have a late- type giant or supergiant primaryand their orbital inclination is well determined from either eclipses orspeckle orbits. They provide the only direct measurements of masses forsuch evolved stars, together with other well-determined physicalparameters. In the computations all effects of enhanced mixing beyondthe convective cores during central hydrogen burning stages, e.g., coreovershooting and any rotationally induced meridional mixing, arerepresented by a simple overshooting prescription. Its single parametercan be constrained to within 25 per cent of its value and leads to anovershooting length l_ov of ~0.24 H_P (pressure scaleheights) for 2.5Msolar, slightly increasing to ~0.32 H_P for 6.5 Msolar. Those valuesare required by our code to reproduce the well-determined luminositiesof the giants in or at the end of their blue loop. This new methodprovides the currently most sensitive test of the overshooting issue.
| Composite spectra Paper 7: HD 190361
HD 190361 is a composite-spectrum binary system in an orbit with a loweccentricity and a period of about 4 yr. We separate the spectra of thecomponent stars and show them to be of types very similar to those in 31Cyg, i.e. near K4Ib and B4IV-V. The relatively small velocity amplitude,together with the rapid rotation and early spectral type of the hotterstar, conspire to make the measurement of the radial velocity of thelatter somewhat imprecise, but we derive a mass ratio of about 1.8 anddeduce that the system is viewed at an inclination of about 36 deg.
| 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.
| An Einstein Observatory SAO-based catalog of B-type stars
About 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars.
| Visual multiples. VIII - 1000 MK types
A total of 1000 new classifications are given for stars brighter than B= 8.0 mag in the Aitken double star catalog. The classificationssupplement 865 classifications obtained in 1981 and 1984. Among thenewly discovered stars are 12 new Ap stars, eight Lambda Bootis stars,one Ba II star, and 60 Am stars. A detailed list of the newclassifications is given.
| Optical observations of ultraviolet objects. II - Classification and photometry /l = 0 to 145 deg/
UBV photometry and MK spectral classification are presented for a sampleof stars originally selected as UV objects from satellite photometrywith the S2/68 experiment. Although most stars of the sample arespectroscopically normal, a number of hot, subluminous stars were alsofound. Radial velocities are given for some of the stars observed. It isproposed that the majority of the apparently normal early B stars athigh galactic latitudes which are not runaway stars are subluminousdisc-population analogues of horizontal branch B stars of Population II.
| Catalogue of early-type stars measured in a narrow-band photometric system
A compilation of the photoelectric measurements in the Barbier-Morguleffsystem is presented. The catalogue includes data for 773 stars ofspectral type 08 to F6. 706 stars have been measured at least twice.
| Ultraviolet photometry from the orbiting astronomical observatory. XVIII - The 1972 eclipse of 31 Cygni
Abstract image available at:http://adsabs.harvard.edu/abs/1975ApJ...195..121D
| UBV Photometry of ζ Aurigae and 31 Cygni
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973PASP...85..131L&db_key=AST
| On the cause underlying the spectral differences of the stars.
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