1 Konkoly Observatory, MTA CSFK, Konkoly Thege M. út 15-17., 1121 Budapest, Hungary
2 Research and Scientific Support Department, ESTEC/ESA, PO Box 299, 2200 AG Noordwijk, The Netherlands
3 Departamento de Astrofísica, Centro de Astrobiología (INTA-CSIC), PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
4 Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía S/N, 18008 Granada, Spain
5 Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
6 INAF – Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate (LC), Italy
7 Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
8 LESIA, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France
9 Institute of Astronomy, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
Received: 29 April 2013
Accepted: 18 June 2013
Context. The high accuracy of space data increased the number of the periodicities determined for pulsating variable stars, but the mode identification is still a critical point in the non-asymptotic regime.
Aims. We use regularities in frequency spacings for identifying the pulsation modes of the recently discovered δ Sct star ID 102749568.
Methods. In addition to analysing CoRoT light curves (15 252 datapoints spanning 131 days), we obtained and analysed both spectroscopic and extended multi-colour photometric data. We applied standard tools (MUFRAN, Period04, SigSpec, and FAMIAS) for time-series analysis.
Results. A satisfactory light-curve fit was obtaining by means of 52 independent modes and 15 combination terms. The frequency spacing revealed distinct peaks around large (25.55–31.43 μHz), intermediate (9.80, 7.66 μHz), and low (2.35 μHz) separations. We directly identified 9 modes, and the l and n values of other three modes were extrapolated. The combined application of spectroscopy, multi-colour photometry, and modelling yielded the precise physical parameters and confirmed the observational mode identification. The large separation constrained the log g and related quantities. The dominant mode is the radial first overtone.
Key words: stars: variables:δScuti / stars: individual: CoRoT 102749568 / stars: oscillations / space vehicles / stars: interiors
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. Discovery and multi-colour follow-up observations were obtained at Piszkéstető, the mountain station of Konkoly Observatory. Spectra were acquired using the AAOmega multi-object spectrograph mounted at the 3.9-m telescope of the Australian Astronomical Observatory in programme 07B/040 and 08B/003 and the HERMES spectrograph, installed at the 1.2-m Mercator Telescope, operated on the island of La Palma by the Flemish Community.
Table 9 is available in electronic form at http://www.aanda.org
© ESO, 2013