C. Catala, Observatoire de Paris, P. Feldman, JHU A. Lecavelier des Etangs, IAP C. Martin, LAM A. Roberge, Carnegie Institution of Washington T. Simon U. Hawaï A. Vidal-Madjar, IAP

FUSE: a spectrograph in the FUV spectral range : Å – R ~

Log L / L  2 Log T eff ß Pictoris A5V, 20 Myr AB Aur A0V, 2.6 Myr HD B9V,  9 Myr HD A1V, 4.7 Myr HD B9V, 2.8 Myr HD B7, 1 Myr HD B5V, 1 Myr HD B5,  1 Myr HD B5,  0.5 Myr HD B2,  0.5 Myr Van den Ancker et al. (1997 & 1998) 20 Herbig Ae/Be stars and a few main sequence stars. HD A B9.5V, 4.7 Myr HR 5999 A5Ve, 0.7 Myr

Evolved objects 7300K 8700K 9800K 10040K 10500K 10700K 12800K Main sequence stars : Main sequence stars : emission lines in the FUV in stars with T eff ≤ 8200 K (Simon et al., 2002) : Pre-main sequence stars : emission lines in stars with T eff ≤ K Bouret, Deleuil, Simon & Catala in preparation

C III

 formation temperatures: up to K  broad : up to +/- 500 km/s

 formation temperatures: up to K  broad : up to +/- 500 km/s HD  complex profiles: bulk of the emission redshifted  variations in intensity: time scale > a few days Deleuil, Lecavelier, Bouret et al., 2004 HD : OVI λ1032

Harper et al., 2001 ; Deleuil et al., 2004b

log10(F(C III)) log10(F(O VI))

 Magnetic field detected in HD (Donati 1997)  some stars have a CS disk imaged;  temperature of a few 10 6 K in the shock region;  variations in the line profiles.  the width of the observed lines is too large! at most equal to the free-fall velocity (Lamzin 1998) mass loss  additional veiling is expected needs to be investigated disk

 mass loss required;  shock region extended with temperature of a few 10 6 K  variations in the line profiles. Babel & Montmerle, 1997  X-rays emission in Ap and Bp stars  similarities of line widths in stars with different vsini !  additional veiling is expected needs to be investigated

Log10( F(O VI)) Log10( Age Myr) Log10( F(O VI)) V sini (km/s) Log10(1/2 M V inf ) ● 2 Log10(F(O VI)) Log10(F(X-rays))

    

Numerous lines in the FUV  The most abundant molecule in the CS environment of young stars  Constrains the reservoir of gas for planets building  Protected by " Self-Shielding " Franck Le Petit, PhD Thesis (2002) J v=0 H 2 in the FUSE spectral domain: Lyman transitions B-X ( ) Werner transitions C-X ( )

 Airglow lines

OVI doublet Å  Airglow lines

Green: Stellar Continuum Blue : Intrinsic Profile Red : Resulting Profile Column densities Radial velocities Line widths (b) Gas bound to the star Owens The Owens Profile Fitting Procedure (M. Lemoine et al. 2002) Martin et al. (2004)

H 2 thermalized up to J=3H 2 thermalized up to J=4

H 2 detected by FUSE: Remnant of the original molecular cloud Very extended disk with an inclination angle: 27°    35° from the plane of the sky (Eisner et al. 2003, Mannings & Sargent 1997) Excitation Conditions = Interstellar Medium Gry et al. (2002)  H 2 thermalized up to J=2  Excitation temperature ~ 50K

HD & HD  Stars surrounded by disks  H 2 Thermalized up to J=4 Collisionally excited medium close to the star < 5 AU (Lecavelier des Etangs, Deleuil et al. 2003)  Disks inclination angles to the lines of sight: (Grady et al. 2000; Augereau et al. 2001) HD :  = 60°  5° HD :  = 51°  3° Extended chromosphere located above the disk ?

HERBIG Be STARS  B8 – B2 stars  H2 Thermalized up to J=3  J=0-3 Temperature: ~100 K  Higher J-levels ~1300 K Very similar to the H 2 excitation in PDRs Bouret, Martin et al. (2003)

RESULTS FOR HD To reproduce the excitation diagram: 2 PDRs are needed: a large PDR with low density for the lower J-levels a dense PDR close to the star for the higher J-levels Compatible with images:  MSX (A band 8.8 µm): Hot dust close to the star  DSS2 (R and I bands): Very large dark cloud Martin et al. (in prep) PHOTODISSOCIATION REGIONS MODEL J. Le Bourlot, "Molecules in the Universe" Team, Observatoire de Paris

 Youngest stars of the sample - HBe Envelopes: remnant of their original cloud HD : PDRs models with 2 components TBD : complete the analysis for the whole sample (under progress)  Stars with circumstellar disk Collisionally excited medium close to the star Goal: explain the excitation diagrams of stars with disk TBD: include radiative transfer of H 2 in models of disk 