1 / 22

Early and Late Be Stars: Investigating Pulsations and Variability at Paris-Meudon Observatory

This research focuses on the study of early (B0-B3) and late (B4-B9) Be stars, examining their pulsations and variability. Early Be stars exhibit detectable pulsations from ground observations, while late Be stars show theoretically predicted but faint signals. Our project leverages photometry and spectroscopy, including data from Hipparcos, COROT, OHP, and LNA, to investigate the effects of rotation and magnetic fields on star pulsations. We aim to identify secondary targets, prioritize early Be stars, and explore their magnetic properties through advanced imaging techniques.

ulfah
Télécharger la présentation

Early and Late Be Stars: Investigating Pulsations and Variability at Paris-Meudon Observatory

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related