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Targets selection Be stars

Targets selection Be stars. Paris-Meudon Observatory: A.-M. Hubert, M. Floquet, C. Neiner Univ. of Valencia : J. Fabregat, J. Gutierrez-Soto, J. Suso Univ. of Sao Paulo : E. Janot-Pacheco, L. Andrade, S. Daflon Royal Observatory of Belgium : Y. Fr é mat ESA, Estec , RSSD: C. Neiner.

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Targets selection Be stars

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  1. Targets selection Be stars Paris-Meudon Observatory: A.-M. Hubert, M. Floquet, C. Neiner Univ. of Valencia: J. Fabregat, J. Gutierrez-Soto, J. Suso Univ. of Sao Paulo: E. Janot-Pacheco, L. Andrade, S. Daflon Royal Observatory of Belgium: Y. Frémat ESA, Estec, RSSD: C. Neiner

  2. Early and late Be stars: 2 science goals • Early Be stars (B0-B3): pulsations and multiperiodicity already detected from the ground • Is the beating effect of close pulsation periods the cause of the Be phenomenon i.e. the presence of a disk around Be stars? • Effects of fast rotation and magnetic field on the pulsations • Late Be stars (B4-B9): pulsations predicted by theory but the amplitude is too small to be detected from the ground  detection of pulsations with Corot!

  3. Photometric variability: Hipparcos (Hubert & Floquet ) • Some of the targets observed by Hipparcos: periodicity found!

  4. Ground-based photometry + variability (Fabregat, Gutierrez-Soto, Suso) • Stromgren photometry at the 0.9m in Granada (6 weeks) for variability: detection of variability, periodicity and even multiperiodicity for HD 168797 and HD 179405 • uvby photometry + narrow filters (Ha, Hb) at the 1.5m in Calar Alto (3 weeks) to search for faint Be stars in the exoplanet fields See Gutierrez-Soto et al. 2003 and posters!

  5. Spectroscopy: GAUDI • for 6 < V < 8 spectra in GAUDI • 17 new Be stars discovered in GAUDI (Neiner, Hubert & Catala, 2004) But: • No spectrum if V > 8 • Does not allow variability study

  6. Additional spectroscopy + variability (Hubert, Janot-Pacheco, Andrade) • Spectroscopic observations at the 1.5m at OHP (6 weeks) • Spectroscopic observations at the 1.6m at LNA (1 week) • Spectrum for Be stars with V > 8 • Detection of variability

  7. Determination of stellar parameters ( Frémat, Neiner, Daflon, Andrade) • Data : GAUDI + OHP + LNA • 2 independent determinations: Frémat & Neiner + Daflon & Andrade • ~70 Be stars in the eyes of Corot (See Frémat, Neiner et al. 2004) 26000 3.75 253

  8. Results for primary fields Centre  Only late Be stars in these primary targets fields.

  9. Anticentre

  10. Centre: • 5 possible late Be stars including 3 well positioned next to the primary targets • no early Be stars Anticentre: • 3 possible late Be stars including 3 well positioned next to the primary targets • 10 possible early Be stars including 3 well positioned next to HD 52265 TOTAL: 18 possible Be stars (8 late, 10 early) including 9 well positioned (6 late and 3 early)

  11. 171219 Field HD 171234 + HD 170580

  12. Field HD 175726 175869

  13. Field 181555 + HD 180642 181367 181231

  14. Field HD 43587 43285 + HD 43913 43913

  15. 47359 Field HD 46558 46484 + HD 47359 46484 45901

  16. 49330 50696 49585 50209 Field HD 49933 + HD 49434  3 early Be stars outside the CCDs with this position of the CCDs

  17. 50891 51193 51452 51404 Field HD 52265 + HD 50891

  18. HR diagram of Be secondary targets + 4 Be stars Apparent Location

  19. HR diagram of Be secondary targets + 4 Be stars Rotation effect W/Wc = 0.95

  20. HR diagram of Be secondary targets = in the CCDs + 2 Be stars in the CCDs + 2 Be stars Real Location

  21. Results for exploratory fields • ~ 60 possible Be targets for exploratory fields • It is better to concentrate on early Be stars, since we have very few early Be stars as secondary targets • 2 already detected with multiperiodicity(Fabregat et al.) : HD 168797 (B3e) and HD 179405 (B5e) • Targets in non-selected primary fields have been well studied  easier candidates

  22. Conclusions • We need early and late Be stars as secondary targets: 2 different science goals • We found variability, periodicity and even multiperiodicity in most of the Be stars, in spectroscopy and in photometry • We plan to search for magnetic fields with Espadons (CFHT) for the Be secondary targets (starting Feb. 2005) • We have 9 out of 18 Be stars (possible secondary targets) which are well positioned in the CCDs, but 6 late and only 3 early • We need to concentrate on early Be stars for the exploratory fields • We already have 2 very interesting exploratory candidates

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