1. Natal 2004/11/011st Brazil-CoRoT meeting1 Seismology of Be stars with CoRoT 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

2. Natal 2004/11/011st Brazil-CoRoT meeting2 Seismology of Be stars with CoRoT Overview of Be stars Be stars as non radial pulsators What do we expect from COROT? Preparatory programmes  in “seismo“ fields  in “exoplanet“ fields Conclusion

3. Natal 2004/11/011st Brazil-CoRoT meeting3 Be stars: main characteristics Population: about 20% of all B-type stars Main sequence or slightly evolved Usually rapidly rotating stars (  c ≥ 0.80) Equatorially concentrated envelope Discrete mass loss events: unknown origin Variability: NRP+ stellar and circumstellar activity Be phase: non permanent character

4. Natal 2004/11/011st Brazil-CoRoT meeting4 Variability in Be stars… Short-term variability present in the quasi-totality of early Be stars, in ~ 50% of mid-types (B4-B5e) and in only 18% of late Be stars (Hipparcos data, Hubert & Floquet 1998) Short periods commonly detected in photometry and spectroscopy Multiperiodicity in light curves and line profiles e.g.  Oph (O9.5Ve), Jankov, Janot-Pacheco, Leister 2000 and MOST data; 19 Mon (B1Ve), Neiner, Hubert, Floquet 2003; Balona et al. 2002

5. Natal 2004/11/011st Brazil-CoRoT meeting5 Example of multiperiodicity in light curves 19 Mon Upper panel:folded in phase with P 1 =0.191d  Lower panel: folded in phase with P 2 =0.204d after removing P 1  NB: P 1 and P 2 also found from ground-based data by Balona et al. 2002 Variation of the magnitude of 19 Mon from Hipparcos data.

6. Natal 2004/11/011st Brazil-CoRoT meeting6 Be stars as non-radial pulsators…   Cephei, SPB (Slow Pulsating B stars), Be stars  Same instability domain (  mechanism)  Line profiles modelling support NRP (e.g. Rivinius et al. 2002, Neiner et al. 2004)

7. Natal 2004/11/011st Brazil-CoRoT meeting7 Be stars as non-radial pulsators… NRP beating and discrete mass loss events?  only one case:  Cen, 15 years of spectroscopic observations modes beating and prediction of epochs of mass loss (Rivinius et al. 1998) 6 periods sorted in 2 groups main mode of each period group: P1=0.5029dl=2, |m|=2  f=0.21, 0.39, 0.60  Hz P5=0.2814dl=3, |m|=3  f=0.33  Hz

8. Natal 2004/11/011st Brazil-CoRoT meeting8  Cen : pulsation beating effect Rivinius et al., 1998 The overall reconstructed amplitude (solid lines); circles:   ; squares:   ; dots:  

9. Natal 2004/11/011st Brazil-CoRoT meeting9 Be stars as magnetic pulsators Magnetically pulsating stars?  2 detections among pulsating early B stars:  Cep (Henrichs et al. 2000): also a slowly rotating Be star! P rot =12d; P puls =0.19d  Ori (Neiner et al. 2003): a « classical » Be star P rot =1.29d; P puls =0.97d magnetic fields: several hundreds of Gauss

10. Natal 2004/11/011st Brazil-CoRoT meeting10 Observed frequencies in  Cep (Telting et al. 1997) f 3 =56.979  Hz f 4 =58.819  Hz f 1 =60.764  Hz f 5 =62.697  Hz f 6 =64.618  Hz f 2 =62.269  Hz magnetic splitting + identification of modes  information on the evolutionary stage - Quintuplet fine structure of f 1, f 3, f 4, f 5, f 6 - f 1 and f 2 : independent }

11. Natal 2004/11/011st Brazil-CoRoT meeting11 H-R diagramme: The stars whose radial mode frequency coincides with the observed frequency f 1 are connected with the solid lignes, and those whose l=2 mode frequency matches with f 2 are shown by the dashed lines. The crossing Points of the solid and dashed lines are the candidate locations for  Cep on the H-R diagramme (from Shibahashi & Aerts, 2000) Radial mode  f 1 (l=2, m=0) mode  f 2

12. Natal 2004/11/011st Brazil-CoRoT meeting12 Seismology with COROT Homogenous data Long-term continuous coverage:  high accuracy on frequency spectrum - multimode detection - beating  it will allow us to disentangle pulsations from stellar activity (corotating clouds) Very high photometric accuracy :  detection of high degree modes of low amplitude Amp 4 in early Be stars (Balona & Kambe 1999)  search of low-amplitude g modes in late Be stars

13. Natal 2004/11/011st Brazil-CoRoT meeting13 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!

14. Natal 2004/11/011st Brazil-CoRoT meeting14 Be stars as potential targets for asteroseismology with COROT About 70 Be stars with 6<V<9.5 in the cones of COROT (seismology fields) including 15 new Be stars with V<8.0 (GAUDI) 18 Be stars as secondary targets candidates for the core programme of asteroseismology Faint Be stars with 12<V<16.5 in the exoplanet fields as part of the Additional Programme

15. Natal 2004/11/011st Brazil-CoRoT meeting15 Preparatory programmes in “seismo“ fields Be stars as secondary targets candidates in primary fields (long runs)  Photometric variability: periodicity, multiperiodicity  Spectroscopic variability: pulsation modes  Determination of fundamental parameters taking into account fast rotation - Abundances  Search of magnetic fields (EsPaDoNS, CFHT) Be stars for exploratory fields (short runs)

16. Natal 2004/11/011st Brazil-CoRoT meeting16 Photometric variability: Hipparcos (Hubert & Floquet )  Some of the targets observed by Hipparcos: periodicity found!

17. Natal 2004/11/011st Brazil-CoRoT meeting17 Ground-based photometry + variability (Fabregat, Gutierrez-Soto, Suso)  Strömgren photometry at the 0.9m in Granada for variability: detection of variability, periodicity and even multiperiodicity for HD 168797 and HD 179405  NB: HD 168797 has been in a B phase for several years!

18. Natal 2004/11/011st Brazil-CoRoT meeting18 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  Additional data for studying variability are needed

19. Natal 2004/11/011st Brazil-CoRoT meeting19 Additional spectroscopy + variability (Hubert, Janot-Pacheco, Andrade)  Spectroscopic observations at the 1.5m at OHP  Spectroscopic observations at the 1.6m at LNA, FEROS, soon EsPaDoNS  Spectrum for Be stars with V > 8  Detection of variability

20. Natal 2004/11/011st Brazil-CoRoT meeting20 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 26000 3.75 253

21. Natal 2004/11/011st Brazil-CoRoT meeting21 Gravitational darkening effects

22. Natal 2004/11/011st Brazil-CoRoT meeting22 (Frémat & Zorec)

23. Natal 2004/11/011st Brazil-CoRoT meeting23

24. Natal 2004/11/011st Brazil-CoRoT meeting24 Centre Main targetBe targetTypeVvsiniTefflog gVariability HD 171234+170580HD 171219B8e7.65300135903.07 HD 171834HD 171219B8e7.65300135903.07 HD 175726HD 175869B9IIIe5.56164118103.25 HD 177552- HD 181555+180642HD 181231B9Ve8.58250136583.73 HD 181367B8e9.36279135003.65  Only late Be stars in these primary targets fields. Results for primary fields

25. Natal 2004/11/011st Brazil-CoRoT meeting25 Anticentre Main targetBe targetTypeVvsiniTefflog gVariability HD 43318- HD 43587HD 43285B6Ve6.07240140003.780.45 d HD 43913A0e7.88 HD 45067- HD 46558HD 45901B2Ve8.8164265183.73phot HD 46484B1Ve7.74120270003.603.29 d HD 47359B0.5Ve8.87 HD 49933+49434HD 49330B0e8.92300270003.820.28 d HD 49585B0.5Ve9.13253260423.750.61 d HD 50209B9Ve8.33180118093.620.66 + 0.59 d HD 50696B1Ve8.83350213003.450.31 d HD 52265HD 50891B0pe8.880.54 d HD 51193B1Vnne8.06215229943.620.61 + 5.5 d HD 51404B3e9.3342225004.20.37 d HD 51452B0IIIne8.08298298873.88spec

26. Natal 2004/11/011st Brazil-CoRoT meeting26 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 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)

27. Natal 2004/11/011st Brazil-CoRoT meeting27 Field HD 171234 + HD 170580 171219

28. Natal 2004/11/011st Brazil-CoRoT meeting28 Field HD 175726 175869

29. Natal 2004/11/011st Brazil-CoRoT meeting29 Field 181555 + HD 180642 181367 181231

30. Natal 2004/11/011st Brazil-CoRoT meeting30 Field HD 43587 43285 43913 + HD 43913

31. Natal 2004/11/011st Brazil-CoRoT meeting31 Field HD 46558 + HD 47359 46484 45901 47359 46484

32. Natal 2004/11/011st Brazil-CoRoT meeting32 Diapositive 29 Field HD 49933 + HD 49434 50209 49330 49585 50696  3 early Be stars outside the CCDs with this position of the CCDs

33. Natal 2004/11/011st Brazil-CoRoT meeting33 Field HD 52265 + HD 50891 51404 51193 51452 50891

34. Natal 2004/11/011st Brazil-CoRoT meeting34 HR diagram of Be secondary targets Apparent Location + 4 Be stars

35. Natal 2004/11/011st Brazil-CoRoT meeting35 HR diagram of Be secondary targets Rotation effect  c = 0.95 + 4 Be stars

36. Natal 2004/11/011st Brazil-CoRoT meeting36 + 2 Be stars in the CCDs + 2 Be stars HR diagram of Be secondary targets Real Location = in the CCDs

37. Natal 2004/11/011st Brazil-CoRoT meeting37 Results for exploratory fields  ~ 60 possible Be targets for exploratory fields (short runs)  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

38. Natal 2004/11/011st Brazil-CoRoT meeting38 Preparatory programmes in exoplanet fields Be stars as targets for seismology in exoplanet fields (12<V<16)  Detection of Be stars in selected fields (in progress)  Determination of fundamental parameters  Selection of the “best “ candidates (early Be stars)  Search of photometric variability

39. Natal 2004/11/011st Brazil-CoRoT meeting39 Detection of Be stars in the exoplanet fields uvby photometry + H ,H  narrow filters by J. Fabregat and collaborators:  Starting point: emission line stars catalogue of Robertson & Jordan (1989)  No information on spectral types is available  Observations at Calar Alto (Almeria, Spain) o Provide spectral classification for RJHA stars o Find new Be stars in exoplanet fields

40. Natal 2004/11/011st Brazil-CoRoT meeting40 Photometry of emission line stars in potential exoplanet fields to identify B stars Diagramme without reddening [m 1 ]-[c 1 ] 5 emission line stars of RJ are B stars

41. Natal 2004/11/011st Brazil-CoRoT meeting41 At least 4 of 5 B emission line stars are confirmed and are probably Be stars + 1 more discovered Diagramme  -  N.B.: Robertson-Jordan stars limited to V<14!

42. Natal 2004/11/011st Brazil-CoRoT meeting42 Detection of Be stars in the exoplanet fields Spectroscopy with VLT/GIRAFFE Part of a programme on the Guaranteed Time Observations of the Observatoire de Paris devoted to spectral classification and precise type identification in exoplanet fields of COROT (G. Alecian P.I., Hubert, Deleuil, Neiner, Floquet, Martayan).  In particular to identify specific groups of stars, Hg-Mn, Be…for Additional Programmes of COROT

43. Natal 2004/11/011st Brazil-CoRoT meeting43 Giraffe: a multi-object spectrograph

44. Natal 2004/11/011st Brazil-CoRoT meeting44 VLT-GIRAFFE spectrograph In Medusa mode: 132 spectra R=6000-30000 Required astrometric precision : 0.2” Field  =26’ Fibers: Minimal separation ~ 12”

45. Natal 2004/11/011st Brazil-CoRoT meeting45 Search for Be stars with VLT-GIRAFFE Domains:  LR06 (644nm - 710nm; R=8600): H  - emission line stars:Be, Ae/Be…  LR02 (397nm - 456nm; R=6400): H , H , blue He I, Mg II - stellar types and fundamental parameters For B9 stars, 1h exposure time, V= 15, S/N  100

46. Natal 2004/11/011st Brazil-CoRoT meeting46 Statistics towards the galactic centre according to the ‘Besançon’ model of stellar population synthesis of the Galaxy (Robin et al. 2003) Giraffe field:  =25’  0.1364 deg 2  2000 =18h50’;   

47. Natal 2004/11/011st Brazil-CoRoT meeting47 Expected detection of Be stars in the exoplanet fields Centre direction ~ 200 Be stars (12<V<16) in 1 deg 2 Exoplanet CCDs ~1.3x2.5 deg 2 Anti-centre direction ~ 30 Be stars (12<V<16) in 1 deg 2 Exoplanet CCDs ~1.3x2.5 deg 2 Estimation from statistics towards the galactic centre and anti-centre according to the ‘Besançon’ model of stellar population synthesis of the Galaxy (Robin et al. 2003)

48. Natal 2004/11/011st Brazil-CoRoT meeting48 Conclusions  We need early and late Be stars as secondary targets: 2 different science goals  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  The final list of faint Be stars for seismology is in preparation; it will be chosen according to the position of the exoplanet CCD’s