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HD 191980 (V1357 Aql)


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On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
The Hipparcos photometry of the Chemically Peculiar main sequence B, A,and F stars is examined for variability. Some non-magnetic CP stars,Mercury-Manganese and metallic-line stars, which according to canonicalwisdom should not be variable, may be variable and are identified forfurther study. Some potentially important magnetic CP stars are noted.Tables 1, 2, and 3 are available only in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html

The HR-diagram from HIPPARCOS data. Absolute magnitudes and kinematics of BP - AP stars
The HR-diagram of about 1000 Bp - Ap stars in the solar neighbourhoodhas been constructed using astrometric data from Hipparcos satellite aswell as photometric and radial velocity data. The LM method\cite{luri95,luri96} allows the use of proper motion and radial velocitydata in addition to the trigonometric parallaxes to obtain luminositycalibrations and improved distances estimates. Six types of Bp - Apstars have been examined: He-rich, He-weak, HgMn, Si, Si+ and SrCrEu.Most Bp - Ap stars lie on the main sequence occupying the whole width ofit (about 2 mag), just like normal stars in the same range of spectraltypes. Their kinematic behaviour is typical of thin disk stars youngerthan about 1 Gyr. A few stars found to be high above the galactic planeor to have a high velocity are briefly discussed. Based on data from theESA Hipparcos astrometry satellite and photometric data collected in theGeneva system at ESO, La Silla (Chile) and at Jungfraujoch andGornergrat Observatories (Switzerland). Tables 3 and 4 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html

The observed periods of AP and BP stars
A catalogue of all the periods up to now proposed for the variations ofCP2, CP3, and CP4 stars is presented. The main identifiers (HD and HR),the proper name, the variable-star name, and the spectral type andpeculiarity are given for each star as far as the coordinates at 2000.0and the visual magnitude. The nature of the observed variations (light,spectrum, magnetic field, etc.) is presented in a codified way. Thecatalogue is arranged in three tables: the bulk of the data, i.e. thosereferring to CP2, CP3, and CP4 stars, are given in Table 1, while thedata concerning He-strong stars are given in Table 2 and those foreclipsing or ellipsoidal variables are collected in Table 3. Notes arealso provided at the end of each table, mainly about duplicities. Thecatalogue contains data on 364 CP stars and is updated to 1996, October31. This research has made use of the SIMBAD database, operated at CDS,Strasbourg, France.

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.

Mesures de vitesses radiales. VII. Accompagnement AU sol DU programme d'observation DU satellite Hipparcos. Radial velocities. VII. Ground based measurements for Hipparcos.
We publish 734 radial velocities of stars distributed in 28 fields of4x4deg. We continue the PPO series (Fehrenbach et al. 1987; Duflot etal. 1990 and 1992), using the Fehrenbach objective prism method.

A new list of effective temperatures of chemically peculiar stars. II.
Not Available

Discovery of the Nature of the Variation of HD 191706
Not Available

Evolutionary status and chemical composition of the atmospheres of He-weak stars.
Not Available

Mid-ultraviolet and optical photometry of helium stars
Mid-ultraviolet and optical photometric analysis of helium stars arepresented. A linear relation exists between the effective temperaturederived from model atmospheres and (1965-V)0 index. The effectivetemperatures derived from (1965-V)0 index are somewhat higher than thatof MK spectral type estimates especially for late B-type helium objects.

Large and kinematically unbiased samples of G- and K-type stars. V - Evolved stars in the selected areas at + 15-deg declination
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990PASP..102..242E&db_key=AST

On the Effective Temperatures of Chemically Peculiar Stars
Not Available

Statistical Investigation of Chemically Peculiar Stars - Part One - the Stars with Known Periods
Not Available

Etoiles a Helium Faible Photometriquement Variables
Not Available

Observational problems of investigation of stars with anomalous helium lines.
Not Available

Catalog of observed periods for the AP stars
A preliminary catalog of the Ap stars, taken in the broad sense toinclude many Bp stars, is presented. The HD and HR numbers,variable-star names, spectral types, and proposed periods are listed;the nature of the periodic variability is indicated; and references tothe observations are provided. Companion stars, confirmed spectroscopicbinaries, and anomalies are mentioned in notes.

65th Name-List of Variable Stars
Not Available

Search for light variability among eight stars with anomalous helium content
A search for periodic light variability was carried out among eightstars with anomalous helium content. No variability was detected duringthe observation period for HD 178993, HD 207538, and HD 209339. Theperiod obtained for HD 184927 by Bond and Levato (1977) was confirmed.For HD 191980, HD 208266, and HD 217833, photometric variability wasdetected and periods were obtained.

The helium-3 stars
An investigation was conducted with the objective to examine a sample ofHe-weak stars, as well as some 'normal' stars in the same temperaturerange. A variety of other hot peculiar objects, including Si and Hg-Mnstars, were also observed. The identification of He-3 is made byaccurately measuring the small isotope shifts of the He I lines in thevisible spectrum. The expected isotope shifts for pure He-3 wereprovided by Fred et al. (1951). Definite He-3 stars include 3 CentauriA, Alpha Sculptoris, Iota Orionis B, HR 1951, HR 2306, HR 7129, HR 7467,and HD 191980. Attention is also given to probable He-3 stars, andquestions regarding the existence of He-3 in silicon stars

Three Newly Discovered Variable Ap Stars
Not Available

The helium-variable star HD 184927.
Abstract image available at:http://adsabs.harvard.edu/abs/1976PASP...88..905B

The Helium-Weak Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJ...175..453M&db_key=AST

Some Spectroscopic Characteristics of the OB Stars: an Investigation of the Space Distribution of Certain OB Stars and the Reference Frame of the Classification
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJS...23..257W&db_key=AST

New Peculiar Stars Noted on Objective-Prism Plates
Not Available

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Datos observacionales y astrométricos

Constelación:Águila
Ascensión Recta:20h12m03.85s
Declinación:+15°21'28.1"
Magnitud Aparente:7.892
Distancia:990.099 parsecs
Movimiento Propio en Ascensión Recta:4.3
Movimiento Propio en Declinación:-2.6
B-T magnitude:7.717
V-T magnitude:7.878

Catálogos y designaciones:
Nombres PropiosV1357 Aql
  (Edit)
HD 1989HD 191980
TYCHO-2 2000TYC 1618-1676-1
USNO-A2.0USNO-A2 1050-16801229
HIPHIP 99540

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