Corot Be stars group Be stars: The team: Secondary targets candidates for the Core Programme of asteroseismology Targets for the Additional Programme The team: 11 members (Belgium, Brazil, France and Spain) People interested in joining our group are welcome! Contact: coralie@ster.kuleuven.be Website: http://www.ster.kuleuven.ac.be/~coralie/corotbe.html CorotWeek8 May 2005 Hubert/Neiner

Be stars as potential targets for the Additional Programme Science goal for Be stars: 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) (Neiner, Hubert, Catala 2005) Candidates for pulsations, rotation, activity, binarity studies (short runs) Faint Be stars with 12<V<16.5 in the exoplanet fields Candidates for asteroseismology (long runs) CorotWeek8 May 2005 Hubert/Neiner

 Preparatory programs for bright Be stars Photometric variability Strömgren photometry (0.9m-T in Granada) : periodicity in early Be stars candidates (Gutierrez-Soto et al. 2003) and even multiperiodicity for NW Ser and V1446 Aql (Fabregat, this COROTWeek) Spectroscopic variability (LNA + OHP+ multisite) Determination of fundamental parameters taking into account fast rotation and veiling (Frémat, et al. 2005) Search for magnetic fields (EsPaDoNS, CFHT) CorotWeek8 May 2005 Hubert/Neiner

Determination of stellar parameters Data : GAUDI + OHP + LNA + FEROS Rapid rotation  stellar flattening + gravitational darkening effects FASTROT (Frémat & Zorec) - assumes: Rigid rotator (Roche model)  log g Von Zeipel law  Teff Local model atmospheres - LTE temperature and pressure distribution (ATLAS9, Kurucz) - NLTE level populations (TLUSTY, Hubeny & Lanz) CS envelope  veiling effect CorotWeek8 May 2005 Hubert/Neiner

From modeling of different spectral domains  Teff, logg, Vsin i and i for a given /c Without correction for rotational effects: Teff = 25450°  1000°K, log g = 3.87  0.10 V sini = 310  30 km/s With corrections for /c= 0.9 (value adopted from Frémat, Zorec et al., in press): Teff = 26000°  1000°K, log g = 4.10  0.10 V sini = 325  30 km/s, i ~ 60° : observed spectrum : fitted spectrum CorotWeek8 May 2005 Hubert/Neiner

Location of Be stars in the HR diagram Without correction for rotational effects With corrections for /c=0.9 CorotWeek8 May 2005

Different Be star spectral distributions between the Galactic Centre and Anticentre  to be related to the insterstellar absorption, more important towards the Galactic Centre (Lucke 1978) Be star’s spectral-type distribution in the cones of COROT (Frémat, Neiner, Hubert, Floquet, Zorec, Janot-Pacheco, de Medeiros, 2005, submitted) CorotWeek8 May 2005 Hubert/Neiner

 Preparatory programmes for faint Be stars Detection of Be stars in the exoplanet fields Spectroscopy at ESO 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, Martayan, Floquet): To validate the method of spectral classification for exoplanet stellar database (Deleuil et al.) To determine fundamental parameters To identify specific groups of stars, Hg-Mn, Be…for Additional Programmes of COROT CorotWeek8 May 2005 Hubert/Neiner

Giraffe: a multi-object spectrograph CorotWeek8 May 2005 Hubert/Neiner

VLT-GIRAFFE: a multi-object spectrograph In Medusa mode: 132 fibers R=7500 and 25000 Required astrometric precision : 0.2” Field =25’ Fibers: Minimal separation ~ 12” CorotWeek8 May 2005 Hubert/Neiner

2 GIRAFFE fields observed (=26’) next to HD 49933+HD 49434  Anticentre direction 2 GIRAFFE fields observed (=26’) next to HD 49933+HD 49434 About 35 B0-A5 candidates in each field (exodat catalog by Deleuil et al.) 2 Be 31 B0-A0 (Teff ≥ 9500°K) H (Alecian, Martayan et al. in preparation) CorotWeek8 May 2005 Hubert/Neiner

Fundamental parameters B stars: -LTE temperature and pressure distributions (ATLAS9, Kurucz) -NLTE level populations (TLUSTY, Hubeny & Lanz) Teff=13615°K, log g=3.95 V sini=65 km/s, RV=49 km/s Example of fit for a B star: : observed spectrum : fitted spectrum CorotWeek8 May 2005 Hubert/Neiner

Be stars: Teff=20860°K, log g=3.93 V sini=260 km/s; RV=55 km/s CorotWeek8 May 2005 Hubert/Neiner

Detection of Be stars in the exoplanet fields… Photometry at Granada, Spain uvby + H,H narrow filters (J. Fabregat, Gutierrez-Soto, Suso) Starting point: emission line stars catalogue of Robertson & Jordan (1989) ( but V<14!) No information on spectral types is available Observations at Calar Alto (Almeria, Spain) Provide spectral classification for RJHA stars Find new Be stars in exoplanet fields CorotWeek8 May 2005 Hubert/Neiner

Diagram without reddening [m1]-[c1] Photometry of emission line stars in potential exoplanet fields to identify B stars Diagram without reddening [m1]-[c1] 5 emission line stars of RJ are B stars (from Fabregat et al. 2003, CorotWeek 4) CorotWeek8 May 2005 Hubert/Neiner

IR photometry with Spitzer - 4 fields observed with IRAC: 2 at HD49933+49434, 2 at HD52265 - 4 IR colors (3.6, 4.5, 5.8 et 8.0 mm) for each field + JHK colors from 2MASS + visible colors and extinction from the exoplanets WG 4 Corot CCDs 2 Spitzer fields CorotWeek8 Hubert/Neiner

2 fields next to HD 49933+49434 CorotWeek8 May 2005 Hubert/Neiner

2 fields next to HD 52265 CorotWeek8 May 2005

Examples Possible Be star observed with Spitzer Typical Be star SED 2MASS Be Black-body B B IR excess (Neiner et al. in preparation) Spitzer colors CorotWeek8 May 2005 Hubert/Neiner

Next Future… Characterization of bright Be stars almost finished Search for faint Be stars still in progress a small number of detections only! But new data! VLT/GIRAFFE spectra (Centre direction), SPITZER data And new proposals! -WFI + ubvyr and H filters at INT, Canaries (Fabregat, Neiner, Gutierrez-Soto et al.) - spectroscopy T1.6m at LNA and T4m-SOAR, (R=6000, visible + R=3000, IR), Brazil + Chile (Janot-Pacheco, Andrade) We need positions of hot stars from exoplanet database! CorotWeek8 May 2005 Hubert/Neiner