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uvby photometry of the mCP stars HD 35298, 19 Lyrae, HD 192678, and HR 8216

Differential Strömgren uvby observations from the Four College Automated Photoelectric Telescope are presented for the mCP stars HD 35298, 19 Lyr, HD 192678, and HR 8216. The period for HD 35298 of 1.85457 days is a revision of North's value while that for 19 Lyr of 7.0980 days is alias of that found by Winzer. HD 192678 is found to be a small amplitude photometric variable with...

Elemental abundance studies of CP stars - II. The silicon stars HD 133029 and HD 192913

Fine analyses of the silicon stars HD 133029 and HD 192913 are presented using ATLAS9 model atmospheres whose predictions fit the optical region spectrophotometry and Hγ profiles and have the same bulk metallicity as the deduced abundances. Both are very He poor stars. The light elements are mostly solar except for silicon, and all the heavier elements, except nickel in HD 133029...

uvby photometry of 33 Tauri, HD 50169, and HR 7786 and an assessment of FCAPT comparison stars

Differential Strömgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for the ellipsoidal variable 33 Tauri, and the magnetic Chemically Peculiar stars HD 50169 and HR 7786. We confirm that Hube's period of 2.975272 days for 33 Tau is correct. HD 50169 is a constant MCP star. HR 7786 is a large amplitude class member confirming...

uvby photometry of 33 Tauri, HD 50169, and HR 7786 and an assessment of FCAPT comparison stars

Differential Strömgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for the ellipsoidal variable 33 Tauri, and the magnetic Chemically Peculiar stars HD 50169 and HR 7786. We confirm that Hube's period of 2.975272 days for 33 Tau is correct. HD 50169 is a constant MCP star. HR 7786 is a large amplitude class member confirming...

HD 18078: A very slowly rotating Ap star with an unusual magnetic field structure

Context. The existence of a significant population of Ap stars with very long rotation periods (up to several hundred years) has progressively emerged over the past two decades. However, only lower limits of the periods are known for most of them because their variations have not yet been observed over a sufficient timebase.Aims. We determine the rotation period of the slowly...

uvby FCAPT photometry of the mCP stars HD 32633,  Aur, 49 Cam, and 3 Hya

uuby FCAPT photometry of the mCP stars HD 32633, θ Aur, 49 Cam, and 3 Hya S. J. Adelman 0 P. Kaewkornmaung 0 0 Department of Physics , The Citadel, 171 Moultrie Street, Charleston, SC 29409 , USA

High-resolution spectroscopic study of red clump stars in the Galaxy: iron-group elements

The main atmospheric parameters and abundances of the iron-group elements (vanadium, chromium, iron, cobalt and nickel) are determined for 62 red giant ‘clump’ stars revealed in the Galactic field by the Hipparcos orbiting observatory. The stars form a homogeneous sample with the mean value of temperature Teff= 4750 ± 160 K, of surface gravity log g= 2.41 ± 0.26 and the mean...

Elemental abundance analyses with DAO spectrograms - XXIX. The mercury-manganese stars 53 Tau, β Tau, γ Crv, and υ Her

&A, 367 , 507 Adelman , S. J. , Gulliver , A. F. , Kochukhov , O. P. , & Ryabchikova , T. A. 2002 , ApJ, 573 , 359 Adelman , S. J. , Adelman , A. S. , & Pintado , O. I. 2003 , A &A, 397 , 267 Asplund ... , 84 , 350 Gulliver , A. F. , Hill , G. , & Adelman , S. J. 1996 , in 5th Vienna Symposium on Stellar Atmospheres and Spectrum Synthesis, ed. S. J. Adelman , F. Kupka , & W. W. Weiss (San Francisco: ASP

uvby photometry of the magnetic chemically peculiar stars HD 37776, HR 2258, HR 6958, and 108 Aquarii

Differential Strömgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for four magnetic chemically peculiar stars. Comparison with uvby photometry of Pedersen & Thomsen for HD 37776 yields an improved period of 1.538675 days. New periods of 15.0305 days and 18.065 days are found for the sharp-lined stars HR 2258 and HR 6958...

uvby photometry of the mCP stars HD 35298, 19 Lyrae, HD 192678, and HR 8216

Differential Strömgren uvby observations from the Four College Automated Photoelectric Telescope are presented for the mCP stars HD 35298, 19 Lyr, HD 192678, and HR 8216. The period for HD 35298 of 1.85457 days is a revision of North's value while that for 19 Lyr of 7.0980 days is alias of that found by Winzer. HD 192678 is found to be a small amplitude photometric variable with...

Elemental abundance analyses with Complejo Astronómico El Leoncito REOSC echelle spectrograms - II. μ Leporis, 7 Sextantis, HR 4817, and 28 Herculis

Elemental abundances are derived for four sharp-lined stars, the Mercury-Manganese stars μ Lep, HR 4817, and 28 Her, and 7 Sex, a Population I star with Population II space motions, using REOSC echelle spectrograms obtained at CASLEO to extend previous studies. Comparisons with published equivalent widths indicate that the CASLEO scale is marginally larger than those of DAO...

Elemental abundance analyses with coadded DAO spectrograms – V. The mercury–manganese stars Phi Herculis, 28 Herculis and HR 7664

Elemental abundance analyses of three mercury–manganese stars were performed in a manner consistent with previous analyses of this series. A few correlations are found between the derived abundances and with the effective temperature in accordance with the expectations of radiative diffusion explanations of the derived abundances. The helium abundances are smaller than the value...

Elemental abundance analyses with DAO spectrograms — XVIII. The double-lined spectroscopic binary 46 Draconis

We present a study of the double-lined spectroscopic binary star 46 Draconis (46 Dra). The variations of the γ-velocity indicate the presence of a third star which revolves around the mutual centre-of-mass of the close binary system with a period of 33.6 yr. Perhaps this third star is responsible for the observed X-ray radiation of 46 Dra. With a temperature difference of only...

Elemental abundance analyses with Complejo Astronomico El Leoncito REOSC echelle spectrograms - III. HR 4487, 14 Hydrae, and 3 Centauri A

Using CASLEO echelle spectrograms, elemental abundances are derived for the sharp-lined non-magnetic CP stars HR 4487, 14 Hya, and 3 Cen A. The first two stars are members of the Mercury-Manganese subgroup and have abundances which are similar to other such peculiar stars. The third is a hotter related star. The detection of Mn II lines in its spectrum adds to this relationship.

Elemental abundance analyses with DAO spectrograms — XIV. The double-lined spectroscopic binary 112 Herculis

T. A. Ryabchikova l L. A. Zakharova 0 S. J. Adelman 1 0 Institute ofAstronomy, Russian Academy ofSciences , Pyatnitskaya str. 48, 109017 Moscow , Russia 2Department ofPhysics , The Citade~ 171