Astron. Astrophys. Suppl. Ser. 130, 223-232

Multiplicity among peculiar A stars^,

I. The Ap stars HD 8441 and HD 137909, and the Am stars HD 43478 and HD 96391

P. North¹ - J.-M. Carquillat² - N. Ginestet² - F. Carrier¹ - S. Udry³

Send offprint request: P. North

1 - Institut d'Astronomie de l'Université de Lausanne, CH-1290 Chavannes-des-bois, Switzerland
2 - Observatoire Midi Pyrénées, 14 avenue Edouard Belin, F-31400 Toulouse, France
3 - Observatoire de Genève, CH-1290 Sauverny, Switzerland

Received October 15; accepted November 25, 1997

Abstract:

We present the first results of a radial-velocity survey of cool Ap and Am stars. HD 8441 is not only a double system with P = 106.357 days, but is a triple one, the third companion having an orbital period larger than 5000 days. Improved orbital elements are given for the classical Ap star HD 137909 = $\beta$ CrB by combining our radial velocities with published ones. We yield new orbital elements of the two Am, SB2 binaries HD 43478 and HD 96391. Good estimates of the individual masses of the components of HD 43478 can be given thanks to the eclipses of this system, for which an approximate photometric solution is also proposed.

Key words: stars: spectroscopic binaries -- stars: eclipsing binaries -- stars: individual: HD 8441, HD 43478, HD 93961, HD 137909