Astron. Astrophys. Suppl. Ser.
Volume 140, Number 3, December II 1999
|Page(s)||279 - 285|
|Published online||15 December 1999|
Contribution à l'étude des spectres composites*
VIII. HD 174016-7, une étoile Ap associée à une géante G Contribution to the study of composite spectra VIII. HD 174016-7, an Ap star with a giant G
Observatoire Midi-Pyrénées, Laboratoire d'astrophysique (UMR 5572), 14 avenue Édouard Belin, F-31400 Toulouse, France
2 The Observatories, Madingley Road, Cambridge CB3 0HA, UK
3 Observatoire de Genève, CH-1290 Sauverny, Suisse
Accepted: 27 August 1999
HD 174016-7, listed by [Hynek (1938)] as a star having a composite spectrum, was on our observing programmes of such objects carried out both at the Cambridge Observatories and at the Observatoire Midi-Pyrénées. Most of the observations were made with the CORAVEL spectrovelocimeter of the Swiss telescope at the Observatoire de Haute-Provence. We find that this star is a long-period spectroscopic binary with two correlation dips; we obtain the following orbital elements: days; T = JD 2450605.2; ; ; km s-1; km s-1; km s-1; Gm; Gm; ; . The primary is a giant star of spectral type near G6III, and the hot dwarf secondary is found to be a peculiar A star of type A0p Sr, Cr, Eu, Si; so HD 174016-7 is, to our knowledge, the second discovered composite-spectrum binary with a Ap-type hot component. A confrontation with Hipparcos data suggests and mv = 0.6 mag. On the basis of very accurate masses of main sequence stars by [Andersen (1991),] we estimate the mass, , of the giant primary, the orbital inclination, , and the mean linear separation of the components, AU. The evolutionary status of the system is discussed using [Schaller et al. (1992)] diagram for stars of solar metallicity. Theoretical masses suggested by this diagram confirm the proposed model.
Key words: stars: individual: HD 174016-7 / binaries: spectroscopic; symbiotic / stars: fundamental parameters
© European Southern Observatory (ESO), 1999