J/A+AS/128/265 J/A+AS/128/265 ubvy-beta photometry of CP2 stars E Masana C Jordi H M Maitzen J Torra Astron. Astrophys. Suppl. Ser. 128 265 1998 1998A&AS..128..265M III/162 : General Catalogue of Ap and Am stars (Renson+ 1991) Photometry, uvby, beta Stars, early-type Stars, peculiar stars: chemically peculiar stars: early-type stars: fundamental parameters The aim of this work is to study the capacity of the uvby H_{beta}_ system for detecting the chemically peculiar (CP) stars based on the effect that peculiar features in the flux distribution have on all the Stroemgren-Crawford indices. Our study focuses on the classical magnetic peculiar stars (CP2), though Am star s (CP1) are also included for comparison with cool CP2 stars. Satisfactory results were obtained for hot CP2 stars: the definition of a new index p, which is a linear combination of uvby H_{beta}_ colours, allowed us to separate a high percentage of hot CP2 stars from normal stars. According to this new index, 60 new CP2 candidates are proposed. The working sample was extracted from The General Catalogue of Ap and Am stars by Renson et al. (1991, Cat. <III/162>). Photometric observations to enlarge the sample of CP2 stars with complete uvby H_{beta}_ photometry were carried out. These observations are also reported in the present paper. The new index p is also used to correct the reddening of early CP2 stars computed as if they were normal stars.

HD Identification (HD number, Cat. <III/135>) --- m_HD Multiplicity index on HD --- HIC Identification (HIC number, Cat. <I/196>) --- m_HIC Multiplicity index on HIC --- SpType Spectral type --- (b-y) (b-y) colour index mag e_(b-y) rms uncertainty (b-y) mag Vmag V magnitude mag e_Vmag rms uncertainty on Vmag mag m1 m1 colour index mag e_m1 rms uncertainty on m1 mag c1 c1 colour index mag e_c1 rms uncertainty on c1 mag o_uvby Number of measurements in uvby --- Hbeta H{beta} colour index mag e_Hbeta rms uncertainty Hbeta mag o_Hbeta Number of measurements in H{beta} --- HD Identification (HD number, Cat. <III/135>) --- m_HD Multiplicity index on HD --- HIC Identification (HIC number, Cat. <I/196>) --- m_HIC Multiplicity index on HIC --- SpType Spectral type --- Hbeta H{beta} colour index mag e_Hbeta rms uncertainty on Hbeta mag o_Hbeta Number of measurements in H{beta} --- Name Identification number=1 references of the numeration for the cluster star in Table 7. Mel 20: Heckmann O., et al., 1956MiHam..10...37H 1956, Mitt. Hamburg. Sternw. Bergedorf, no. 10 NGC 1893: Cuffey J., 1937AnHar.105..403C NGC 2244: Ogura K., Ishida K., 1981PASJ...33..149O NGC 2516: Cox A.N., 1955ApJ...121..628C NGC 3293: Turner D.G., et al., 1980AJ.....85.1193T NGC 3766: Ahmed F., 1962PROE....3...57A NGC 6231: Seggewis W., 1968VeBon..79....1S NGC 7039: Hassan S.M., 1973A&AS....9..261H NGC 7243: Lengauer G.G., 1937, Izv. Glav. Astr. Obs. Pulkove 15, no. 126 =1937BOPul..15....3L NGC 7654: Lundby A., 1946UppAn...1j...1L IC 4725: Johnson H.L., 1960ApJ...131..620J --- OtherName Alternative identification number=1 references of the numeration for the cluster star in Table 7. Mel 20: Heckmann O., et al., 1956MiHam..10...37H 1956, Mitt. Hamburg. Sternw. Bergedorf, no. 10 NGC 1893: Cuffey J., 1937AnHar.105..403C NGC 2244: Ogura K., Ishida K., 1981PASJ...33..149O NGC 2516: Cox A.N., 1955ApJ...121..628C NGC 3293: Turner D.G., et al., 1980AJ.....85.1193T NGC 3766: Ahmed F., 1962PROE....3...57A NGC 6231: Seggewis W., 1968VeBon..79....1S NGC 7039: Hassan S.M., 1973A&AS....9..261H NGC 7243: Lengauer G.G., 1937, Izv. Glav. Astr. Obs. Pulkove 15, no. 126 =1937BOPul..15....3L NGC 7654: Lundby A., 1946UppAn...1j...1L IC 4725: Johnson H.L., 1960ApJ...131..620J --- SpType Spectral type --- DELTAp Delta p (peculiarity parameter) mag Patricia Bauer CDS 1997Jul24Eduard Masana <emasana@fajtr0.am.ub.es> J_A+AS_128_265.xml