EDP Sciences
Free access
Volume 425, Number 1, October I 2004
Page(s) 171 - 177
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20035922

A&A 425, 171-177 (2004)
DOI: 10.1051/0004-6361:20035922

HD 153720 - A SB2 system with twin metallic-line components

A. V. Yushchenko1, 2, V. F. Gopka2, V. L. Khokhlova3, D. L. Lambert4, C. Kim5 and Y. W. Kang1

1  Department of Astronomy, Sejong University, Seoul, 143-747, Korea
    e-mail: yua@arcsec.sejong.ac.kr; kangyw@sejong.ac.kr
2  Odessa Astronomical Observatory, Odessa National University, Park Shevchenko, Odessa, 65014, Ukraine
    e-mail: yua@odessa.net; gopkavera@mail.ru
3  Deceased (Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya ul. 48, Moscow, 109017, Russia)
4  The W. J. McDonald Observatory, University of Texas, Austin, TX 78712, USA
    e-mail: dll@astro.as.utexas.edu
5  Department of Earth Science Education, Chonbuk National University, Chonju 561-756, Korea
    e-mail: chkim@astro.chonbuk.ac.kr

(Received 20 December 2003/ Accepted 25 May 2004 )

We report the results of abundance determinations for the components of the SB2 star HD 153720 from high resolution ( $R=60\,000$) echelle high signal-to-noise spectra of the wavelength region 3595-10 260 Å taken with the 2.7 m telescope of the McDonald Observatory We found the values of the atmospheric parameters of the primary to be effective temperature $T_{{\rm eff}}$ = 7425 K and surface gravity $\log\,g$ = 4.0 cgs, and of the secondary to be $T_{{\rm eff}}$ = 7125 K and $\log\,g$ = 3.9 cgs. The microturbulent velocity is $v_{{\rm micro}}$ = 2.7  ${{\rm km~s^{-1}}}$ for both components, and the projected rotational velocity is ${v\sin i}$  = 15  ${{\rm km~s^{-1}}}$ also for both components. The abundances of about 20 elements were determined with the method of spectrum synthesis. The components of HD 153720 are metallic-line stars. Possible inconsistencies between old and new measurements of radial velocities may be explained by the existence of third body in this system. A review of recent high resolution spectral observations of eight A4-F1 binaries shows that only one of these systems can be classified as normal.

Key words: stars: abundances -- stars: atmospheres -- stars: evolution -- stars: chemically peculiar -- stars: binaries: spectroscopic -- stars: individual: HD 153720 

SIMBAD Objects

© ESO 2004