new insights into the close circumstellar environment of the herbig ae/be stars
DESCRIPTION
New insights into the close circumstellar environment of the Herbig Ae/Be stars. M. Deleuil, J.C. Bouret Laboratoire d'Astrophysique de Marseille. C. Catala, Observatoire de Paris, P. Feldman, JHU A. Lecavelier des Etangs, IAP C. Martin, LAM. - PowerPoint PPT PresentationTRANSCRIPT
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• 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
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FUSE: a spectrograph in the FUVspectral range : 910 - 1180Å – R ~
15 000
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3.63.844.24.44.6
4
1
3
Lo
g L
/ L
2
Log Teff
ßß Pictoris PictorisA5V, 20 Myr
AB AurAB AurA0V, 2.6 Myr
HD 100546HD 100546B9V, 9 Myr
HD 163296HD 163296 A1V, 4.7 Myr
HD 176386HD 176386B9V, 2.8 Myr
HD 250550HD 250550B7, 1 Myr
HD HD 8556785567
B5V, 1 Myr
HD HD 259431259431
B5, 1 Myr
HD 38087HD 38087B5, 0.5 Myr
HD 76534HD 76534B2, 0.5 Myr
Van den Ancker et al. (1997 & 1998)
20 Herbig Ae/Be stars and a few main sequence stars.
HD 141569AHD 141569AB9.5V, 4.7 Myr HR 5999HR 5999
A5Ve, 0.7 Myr
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Evolved objects
7300K
8700K
9800K
10040K
10500K
10500K
10700K
12800K
Main sequence starsMain sequence stars : : emission lines in the FUV in stars with Teff ≤ 8200 K (Simon et al., 2002)
Pre-main sequence stars : : emission lines in stars with Teff ≤ 11 500 K
Bouret, Deleuil, Simon & Catala in preparation
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C III
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formation temperatures:
up to 300 000K
broad :
up to +/- 500 km/s
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formation temperatures:
up to 300 000K
broad :
up to +/- 500 km/s
HD 100546
complex profiles:
bulk of the emission
redshifted
variations in intensity:
time scale > a few days
Deleuil, Lecavelier, Bouret et al., 2004
HD 100546 : OVI λ1032
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Harper et al., 2001 ; Deleuil et al., 2004b
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log10(F(C III))
log1
0(F
(O V
I))
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Magnetic field detected in HD 104237
(Donati 1997)
some stars have a CS disk imaged; temperature of a few 106 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
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mass loss required; shock region extended with
temperature of a few 106 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
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Log10
( F(
O V
I))
Log10( Age Myr)
Log10
( F(
O V
I))
V sini (km/s)Log10(1/2 M Vinf)● 2
Log10
(F(O
VI)
)
Log10(F(O VI))
Log10
(F(X
-rays)
)
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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
H2 in the FUSE spectral domain:
Lyman transitions B-X ( )
Werner transitions C-X ( )
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Airglow lines
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OVI doublet 1032-1038 Å
Airglow lines
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Green: Stellar Continuum
Blue : Intrinsic Profile
Red : Resulting Profile
Column densities
Radial velocities
Line widths (b)
Gas bound to the star
The OwensOwens Profile Fitting Procedure (M. Lemoine et al. 2002)
Martin et al. (2004)
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H2 thermalized up to J=3H2 thermalized up to J=4
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HH22 detected by FUSE: 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 ConditionsExcitation Conditions ==
Interstellar MediumInterstellar MediumGry et al. (2002)
H2 thermalized up to J=2
Excitation temperature ~ 50K
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HD 100546 & HD 163296HD 100546 & HD 163296
Stars surrounded by disks
H2 Thermalized up to J=4
Collisionally excited medium close to the star < 5 AU
(Lecavelier des Etangs, Deleuil et al. 2003)
Disks inclination angles tothe lines of sight:
(Grady et al. 2000; Augereau et al. 2001)
• HD 163296: = 60° 5°
• HD 100546: = 51° 3°
Extended chromosphere
located above the disk ?
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HERBIG Be STARSHERBIG 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 HVery similar to the H22
excitationexcitation in PDRs in PDRs
Bouret, Martin et al. (2003)
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RESULTS FOR HD 259431RESULTS FOR HD 259431
To reproduce the excitation diagram:
2 PDRs are needed: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: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
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Youngest stars of the sample - HBeEnvelopes: remnant of their original cloud
HD 259431: PDRs models with 2 componentsTBD : 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 diskTBD: include radiative transfer of H2 in models of disk