Issue |
Astron. Astrophys. Suppl. Ser.
Volume 140, Number 3, December II 1999
|
|
---|---|---|
Page(s) | 279 - 285 | |
DOI | https://doi.org/10.1051/aas:1999424 | |
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
1
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
Received:
23
July
1999
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