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HD 128997


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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

First CCD measurements in the {DELTA}a system for detecting CP2 stars.
This is the first time that CCD-photometry in the three filter {DELTA}asystem (Maitzen, 1976A&A....52..223M) was carried out after twodecades of classical photoelectric photometry. The aim is to extend thesuccessful search for chemically peculiar stars to more and distant openclusters as well as far galactic fields. In this paper we presentCCD-photometry for a sample of 25 field stars with publishedspectroscopic peculiarity types. 22 of them show discordance betweentheir Michigan catalogue types (non-peculiar) and the Bidelman &MacConnell (1973AJ.....78..678B; BC) peculiarity assignments. Eightstars are peculiar in {DELTA}a (five of them also in the Geneva index{DELTA}(V1-G)) thus supporting BC, mainly among their Silicon stardiscoveries. Considering cases where Silicon line enhancements wereinterpreted as peculiar instead as indicator of higher luminosity by BC,and the perfect detection of the three unambiguous peculiar stars, inaddition to the achievement of an accuracy of 0.003mags, we arejustified to conclude that the performance of our CCD-{DELTA}aphotometry perfectly matches the requirements of the conventionalphotometric technique and thus opens the way to observations of fainterstars.

Double star observations at the Lamont-Hussey Observatory of the University of Michigan at Bloemfontein, South Africa.
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관측 및 측정 데이터

별자리:컴퍼스자리
적경:14h43m23.03s
적위:-66°46'43.0"
가시등급:8.865
거리:943.396 파섹
적경상의 고유운동:-8.3
적위상의 고유운동:-2.4
B-T magnitude:8.985
V-T magnitude:8.875

천체목록:
일반명   (Edit)
HD 1989HD 128997
TYCHO-2 2000TYC 9019-1663-1
USNO-A2.0USNO-A2 0225-20771497
HIPHIP 71990

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