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Contribution a l'etude de la binarite des etoiles de type Am. I. HD 125273, binaire spectroscopique a raies doubles
We present an observing program undertaken at Observatoire deHaute-Provence, for the search and study of spectroscopic binaries amongAm stars. HD 125273 was recognized as an Am star some time ago\cite[(Olsen 1980;]{ols80} \cite[Abt 1984);]{abt84} observations,carried out with the CORAVEL spectrovelocimeter, show that this star isa double-lined spectroscopic binary; its orbital elements are asfollows: P = 7.482664 days; T = 2448665.660 JD; omega_1 = 355.3() deg; e= 0.071; K_1 = 49.82 km/s; K_2 = 51.75 km/s; V_0 = -17.42 km/s; a_1 sini= 5.113 Gm; a_2 sini = 5.311 Gm; M_1 sin(3i) = 0.412 M_sun;; M_2 sin(3i)= 0.396 M_sun. Stroemgren photometry of the star \cite[(Olsen1983)]{ols83} permits us to estimate the following mean physicalparameters for the components of the binary: T_eff = 7500 K; log g =3.70; M_v = 1.24; M = 2.1 M_sun;; R = 3.2 R_sun, and to specify theevolutionary status of the system. Assuming the above mass for thecomponents, we found i ~ 35() deg and a ~ 26 R_sun. This system is thusa detached one without possibility of eclipses. It is likely that thetwo components are Am stars of very close characteristics. The v sinivalues, determined from the correlation dips given by CORAVEL, are near11 km/s for both components. We retain for this binary the hypothesis ofrotation-revolution synchronism, because it leads to a value of theradius of the stars in agreement both with the above value and theresults of a previous study by \cite[Kitamura & Kondo (1978)]{kit78}of similar, but eclipsing, systems. The ratio of the correlation dipareas indicates a magnitude difference Delta m_v ~ 0.2 mag. As expectedin detached systems of main sequence stars, such as Am's, HD 125273obeys the mass-luminosity law. Etude effectuee a partir d'observationsfaites a l'Observatoire de Haute-Provence.
| Mesures de vitesses radiales. VIII. Accompagnement AU sol DU programme d'observation DU satellite HIPPARCOS
We publish 1879 radial velocities of stars distributed in 105 fields of4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbachet al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90}using the Fehrenbach objective prism method. Table 1 only available inelectronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Spectroscopic tests of photoelectric stellar classification of abnormal stars
Spectroscopic classification is obtained for 169 northern A5-G0 starspredicted by Olsen (1979, 1980) to have abnormal spectra on the basis ofStromgren four-color photometry. The success in identifying reddenedearly type stars was nearly 100 percent, for Am and early type weaklined stars about 75 percent, for stars above main sequence about 50percent, for composite spectra about 25 percent, and for Ap and LambdaBoo stars 0 percent. Thus photoelectric photometry is a successful firststep in discovering stars of the more extreme spectroscopicabnormalities.
| Estimation of spectral classifications for bright northern stars with interesting Stromgren indices
The purpose of this investigation is to provide spectroscopic observerswith finding lists of potentially interesting objects. From anunpublished UVBY catalogue of 7026 northern stars (mostly brighter than8.3m) 1094 objects with interesting combinations of UVBY indices havebeen selected. Most stars with post-HD classifications have beenexcluded, as well as late F dwarfs belonging to the intermediatepopulation II. For the 792 remaining stars estimated spectralclassifications are given. The techniques and experience from a previouspaper dealing with southern stars have been utilized here. Among thepredicted spectral classifications are 40 OB stars; 262 Ap, Am, or Fmstars; 16 supergiants of types A to G; 110 bright giants of types A to K(class II); 156 double stars or objects with composite spectra; 26 lateF dwarfs; 91 weak-lined dwarf and giant stars of types F to K, includingearly F-type population II field blue stragglers; and a few possiblefield horizontal branch stars, lambda Bootis-type stars, and late-typehalo giants.
| Photo-electric colours of B- and A-type stars in a number of Selected Areas
Not Available
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| קבוצת-כוכבים: | שומר הדובים |
| התרוממות ימנית: | 14h16m44.79s |
| סירוב: | +53°15'48.8" |
| גודל גלוי: | 7.854 |
| מרחק: | 315.457 פארסק |
| תנועה נכונה: | -12.9 |
| תנועה נכונה: | -0.5 |
| B-T magnitude: | 8.196 |
| V-T magnitude: | 7.883 |
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