Bibcode
García Hernández, A.; Moya, A.; Michel, E.; Suárez, J. C.; Poretti, E.; Martín-Ruíz, S.; Amado, P. J.; Garrido, R.; Rodríguez, E.; Rainer, M.; Uytterhoeven, K.; Rodrigo, C.; Solano, E.; Rodón, J. R.; Mathias, P.; Rolland, A.; Auvergne, M.; Baglin, A.; Baudin, F.; Catala, C.; Samadi, R.
Bibliographical reference
Astronomy and Astrophysics, Volume 559, id.A63, 14 pp.
Advertised on:
11
2013
Journal
Citations
56
Refereed citations
42
Description
Aims: The aim of this work was to use a multi-approach technique
to derive the most accurate values possible of the physical parameters
of the δ Sct star HD 174966, which was observed with the CoRoT
satellite. In addition, we searched for a periodic pattern in the
frequency spectra with the goal of using it to determine the mean
density of the star. Methods: First, we extracted the frequency
content from the CoRoT light curve. Then, we derived the physical
parameters of HD 174966 and carried a mode identification out from the
spectroscopic and photometric observations. We used this information to
look for the models fulfilling all the conditions and discussed the
inaccuracies of the method because of the rotation effects. In a final
step, we searched for patterns in the frequency set using a Fourier
transform, discussed its origin, and studied the possibility of using
the periodicity to obtain information about the physical parameters of
the star. Results: A total of 185 peaks were obtained from the
Fourier analysis of the CoRoT light curve, all of which were reliable
pulsating frequencies. From the spectroscopic observations, 18
oscillation modes were detected and identified, and the inclination
angle (62.5°-17.5+7.5) and the rotational
velocity of the star (142 km s-1) were estimated. From the
multi-colour photometric observations, only three frequencies were
detected that correspond to the main ones in the CoRoT light curve. We
looked for periodicities within the 185 frequencies and found a
quasiperiodic pattern Δν ~ 64 μHz. Using the inclination
angle, the rotational velocity, and an Echelle diagram (showing a double
comb outside the asymptotic regime), we concluded that the periodicity
corresponds to a large separation structure. The quasiperiodic pattern
allowed us to discriminate models from a grid. As a result, the value of
the mean density is achieved with a 6% uncertainty. So, the Δν
pattern could be used as a new observable for A-F type stars.
The CoRoT space mission was developed and is operated by the French
space agency CNES, with participation of ESA's RSSD and Science
Programmes, Austria, Belgium, Brazil, Germany, and Spain.This work is
based on ground-based observations made with the ESO 3.6 m telescope at
La Silla Observatory under the ESO Large Programme LP182.D-0356, and on
observations collected at the Centro Astronómico Hispano
Alemán (CAHA) at Calar Alto, operated jointly by the
Max-Planck-Institut für Astronomie and the Instituto de
Astrofísica de Andalucía (CSIC), and on observations made
at Observatoire de Haute Provence (CNRS), France, and at Observatorio de
Sierra Nevada (OSN), Spain, operated by the Instituto de
Astrofísica de Andalucía (CSIC). This research has made
use of both the Simbad database, operated at CDS, Strasbourg, France,
and the Astrophysics Data System, provided by NASA, USA.Table 6 is only
available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A63
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