Improved variability classification of CoRoT targets with Giraffe spectra

  1. Sarro, L.M. 4
  2. Debosscher, J. 5
  3. Neiner, C. 6
  4. Bello-García, A. 3
  5. González-Marcos, A. 2
  6. Prendes-Gero, B. 3
  7. Ordieres, J. 7
  8. León, Gonzalo. 4
  9. Aerts, C. 15
  10. De Batz, B. 6
  1. 1 Radboud University Nijmegen
    info

    Radboud University Nijmegen

    Nimega, Holanda

    ROR https://ror.org/016xsfp80

  2. 2 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

  3. 3 Universidad de Oviedo
    info

    Universidad de Oviedo

    Oviedo, España

    ROR https://ror.org/006gksa02

  4. 4 Universidad Nacional de Educación a Distancia
    info

    Universidad Nacional de Educación a Distancia

    Madrid, España

    ROR https://ror.org/02msb5n36

  5. 5 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
  6. 6 Laboratory of Space Studies and Instrumentation in Astrophysics
    info

    Laboratory of Space Studies and Instrumentation in Astrophysics

    Meudon, Francia

    ROR https://ror.org/02eptjh02

  7. 7 Universidad Politécnica de Madrid
    info

    Universidad Politécnica de Madrid

    Madrid, España

    ROR https://ror.org/03n6nwv02

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Revista:
Astronomy and astrophysics

ISSN: 0004-6361

Ano de publicación: 2013

Volume: 550

Tipo: Artigo

DOI: 10.1051/0004-6361/201220184 SCOPUS: 2-s2.0-84879661040 WoS: WOS:000314879700120 GOOGLE SCHOLAR lock_openAcceso aberto editor

Outras publicacións en: Astronomy and astrophysics

Resumo

Aims.We present an improved method for automated stellar variability classification, using fundamental parameters derived from high resolution spectra, with the goal to improve the variability classification obtained using information derived from CoRoT light curves only. Although we focus on Girae spectra and CoRoT light curves in this work, the methods are much more widely applicable. Methods. In order to improve the variability classification obtained from the photometric time series, only rough estimates of the stellar physical parameters (Teff and log (g)) are needed because most variability types that overlap in the space of time series parameters, are well separated in the space of physical parameters (e.g. γ Dor/SPB or δ Sct/β Cep). In this work, several state-of-the-art machine learning techniques are combined to estimate these fundamental parameters from high resolution Giraffe spectra. Next, these parameters are used in a multi-stage Gaussian-Mixture classifier to perform an improved supervised variability classification of CoRoT light curves. The variability classifier can be used independently of the regression module that estimates the physical parameters, so that non-spectroscopic estimates derived e.g. from photometric colour indices can be used instead. Results. Teff and log (g) are derived from Giraffe spectra, for 6832 CoRoT targets. The use of those parameters in addition to information extracted from the CoRoT light curves, significantly improves the results of our previous automated stellar variability classification. Several new pulsating stars are identified with high confidence levels, including hot pulsators such as SPB and β Cep, and several γ Dor-δ Sct hybrids. From our samples of new γ Dor and δ Sct stars, we find strong indications that the instability domains for both types of pulsators are larger than previously thought. © 2013 ESO.