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HD 44989


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CP2 stars as viewed by the UVBY H_beta system
The aim of this work is to study the capacity of the uvby H_βsystem for detecting the chemically peculiar (CP) stars based on theeffect that peculiar features in the flux distribution have on all theStromgren-Crawford indices. Our study focuses on the classical magneticpeculiar stars (CP2), though Am stars (CP1) are also included forcomparison with cool CP2 stars. Satisfactory results were obtained forhot CP2 stars: the definition of a new index p, which is a linearcombination of uvby H_β colours, allowed us to separate a highpercentage of hot CP2 stars from normal stars. According to this newindex, 60 new CP2 candidates are proposed. The working sample wasextracted from The General Catalogue of Ap and Am stars by \cite[Rensonet al. (1991)]{ren91}. Photometric observations to enlarge the sample ofCP2 stars with complete uvby H_β photometry were carried out. Theseobservations are also reported in the present paper. The new index p isalso used to correct the reddening of early CP2 stars computed as ifthey were normal stars. Tables 2, 3 and 7 are also available inelectronic form from CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Color excesses of classical cepheids. I
The color excesses of eleven cepheids have been determined with the aidof photometry of field stars found in the proximity of the variables. Acomparison of the color excesses with previous color-excess results isgiven. Four cepheids: RT Aur, DT Cyg, Zeta Gem, and T Vul, haverelatively small and well-established reddening values. These fourstars, along with Alpha UMi, can serve as standards to calibratereddening-free indices with intrinsic color indices such as (b-y) or(B-V).

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Osservazione e dati astrometrici

Costellazione:Unicorno
Ascensione retta:06h25m16.28s
Declinazione:+07°37'49.7"
Magnitudine apparente:9.35
Moto proprio RA:0.9
Moto proprio Dec:-0.2
B-T magnitude:9.406
V-T magnitude:9.355

Cataloghi e designazioni:
Nomi esatti   (Edit)
HD 1989HD 44989
TYCHO-2 2000TYC 732-1340-1
USNO-A2.0USNO-A2 0975-03167259

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