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Star and Planet Formation Sommer term 2007 Henrik Beuther & Sebastian Wolf 16.4 Introduction (H.B. & S.W.) 23.4 Physical processes, heating and cooling, radiation transfer (H.B.) 30.4 Gravitational collapse & early protostellar evolution I (H.B.) 07.5 Gravitational collapse & early protostellar evolution II (H.B.) 14.5 Protostellar and pre-main sequence evolution (H.B.) 21.5 Outflows and jets (H.B.) 28.5 Pfingsten (no lecture) 04.6 Clusters, the initial mass function (IMF), massive star formation (H.B.) 11.6 Protoplanetary disks: Observations + models I (S.W.) 18.6 Gas in disks, molecules, chemistry, keplerian motions (H.B.) 25.6 Protoplanetary disks: Observations + models II (S.W.) 02.7 Accretion, transport processes, local structure and stability (S.W.) 09.7 Planet formation scenarios (S.W.) 16.7 Extrasolar planets: Searching for other worlds (S.W.) 23.7 Summary and open questions (H.B. & S.W.) More Information and the current lecture files: http://www.mpia.de/homes/beuther/lecture_ss07.htmlhttp://www.mpia.de/homes/beuther/lecture_ss07.html and http://www.mpia.de/homes/swolf/vorlesung/sommer2007.htmlhttp://www.mpia.de/homes/swolf/vorlesung/sommer2007.html Emails: beuther@mpia.de, swolf@mpia.de
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Accretion disks Beckwith et al. 1990 1.3mm IRAS NIR Full line: no inner whole Dashed line: Inner whole Early single-dish observations toward T-Tauri stars revealed cold dust emission. In spherical symmetry this would not be possible since the corresponding gas and dust would extinct any emission from the central protostar. --> Disk symmetry necessary!
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Simple case: flat, black disk T ~ r -3/4, L disk ~ 1/4 L * Model SEDs Beckwith et al. 1996, 1999
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Effects of gaps on disk SED Full line: no gap Long-dashed: gap 0.75 to 1.25 AU Short-dashed: gap 0.5 to 2.5 AU Dotted: gap 0.3 to 3 AU To become detectable gap has to cut out at least a decade of disk size.
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Additional FIR excess - Larger inner or smaller outer disk radii even increase the discrepancy. - Data indicate that outer disk region is hotter than expected from flat, black disk model --> Disk flaring
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Disk flaring The scale height h of a disk increases with radius r because the thermal energy decreases more slowly with increasing radius r than the vertical component of the gravitational energy: E vert, grav ~ h/r * GM * /r ~ E therm ~ kT(r) with T(r) ~ r -3/4 --> h ~ k/GM * r 5/4
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Hydrostatic equilibrium, radiative transfer models for flared disks I Chiang & Goldreich 1997
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Hydrostatic equilibrium, radiative transfer models for flared disks II Chiang & Goldreich 1997 h n vert ~ exp(z 2 /2h 2 )
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Hydrostatic equlibrium, radiative transfer models for flared disks III Chiang & Goldreich 1997
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Flat spectrum disks Class I protostar Class II T Tauri star Outflow cavity Infalling envelope disk - Flat-spectrum sources have too much flux to be explained by heating of protostar only. - In very young sources, they are still embedded in infalling envelope --> this can scatter light and cause additional heating of outer disk. Flat spectrum sources younger than typical class II T Tauri stars. Calvet et al. 1994, Natta et al. 1993
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Molecules in Space 2 3 4 5 6 7 8 9 10 11 12 13 atoms -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- H2 C3 c-C3H C5 C5H C6H CH3C3N CH3C4H CH3C5N? HC9N CH3OC2H5 HC11N AlF C2H l-C3H C4H l-H2C4 CH2CHCN HCOOCH3 CH3CH2CN (CH3)2CO AlCl C2O C3N C4Si C2H4 CH3C2H CH3COOH? (CH3)2O NH2CH2COOH? C2 C2S C3O l-C3H2 CH3CN HC5N C7H CH3CH2OH CH3CH2CHO CH CH2 C3S c-C3H2 CH3NC HCOCH3 H2C6 HC7N CH+ HCN C2H2 CH2CN CH3OH NH2CH3 CH2OHCHO C8H CN HCO CH2D+? CH4 CH3SH c-C2H4O CH2CHCHO CO HCO+ HCCN HC3N HC3NH+ CH2CHOH CO+ HCS+ HCNH+ HC2NC HC2CHO CP HOC+ HNCO HCOOH NH2CHO CSi H2O HNCS H2CHN C5N HCl H2S HOCO+ H2C2O HC4N KCl HNC H2CO H2NCN NH HNO H2CN HNC3 NO MgCN H2CS SiH4 NS MgNC H3O+ H2COH+ NaCl N2H+ NH3 OH N2O SiC3 PN NaCN C4 SO OCS SO+ SO2 SiN c-SiC2 SiO CO2 SiS NH2 CS H3+ HF SiCN SH AlNC FeO(?) SiNC Currently 129 detected interstellar molecules (from November 2005)
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Molecules in disks 2 3 4 5 6 7 8 9 10 11 12 13 atoms -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- H2 C3 c-C3H C5 C5H C6H CH3C3N CH3C4H CH3C5N? HC9N CH3OC2H5 HC11N AlF C2H l-C3H C4H l-H2C4 CH2CHCN HCOOCH3 CH3CH2CN (CH3)2CO AlCl C2O C3N C4Si C2H4 CH3C2H CH3COOH? (CH3)2O NH2CH2COOH? C2 C2S C3O l-C3H2 CH3CN HC5N C7H CH3CH2OH CH3CH2CHO CH CH2 C3S c-C3H2 CH3NC HCOCH3 H2C6 HC7N CH+ HCN C2H2 CH2CN CH3OH NH2CH3 CH2OHCHO C8H CN HCO CH2D+? CH4 CH3SH c-C2H4O CH2CHCHO CO HCO+ HCCN HC3N HC3NH+ CH2CHOH CO+ HCS+ HCNH+ HC2NC HC2CHO CP HOC+ HNCO HCOOH NH2CHO CSi H2O HNCS H2CHN C5N HCl H2S HOCO+ H2C2O HC4N KCl HNC H2CO H2NCN NH HNO H2CN HNC3 NO MgCN H2CS SiH4 NS MgNC H3O+ H2COH+ NaCl N2H+ NH3 OH N2O SiC3 PN NaCN C4 SO OCS SO+ SO2 SiN c-SiC2 SiO CO2 SiS NH2 CS H3+ HF SiCN SH AlNC FeO(?) SiNC DCO+ Currently 129 detected interstellar molecules (from November 2005)
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Disk dynamics: Keplerian motion Simon et al.2000 For a Keplerian supported disk, centrifugal force should equal grav. force. F cen = mv 2 /r = F grav = Gm * m/r 2 --> v = (Gm * /r) 1/2 Velocity Offset Ohashi et al. 1997 Guilloteau et al. 1998 DM Tau
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Non-Keplerian motion: AB Aur PdBI, Pietu et al. 2005 SMA, Lin et al. 2006 345GHz continuum SMA, Lin et al. 2006 CO(3-2) - Central depression in cold dust and gas emission. - Non-Keplerian velo- city profile v r -0.4+-0.01 - Possible explanations Formation of low- mass companion or planet in inner disk. Early evolutionary phase where Keplerian motion is not established yet (large envelope).
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Disk-jet co-rotation in DG Tau Bacciotti et al. 2002 blue red Testi et al. 2002 Corotation of disk and jet
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Disk structure Pietu et al. 2007 Different lines trace different optical depth.
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Relatively robust results - Disk sizes between 200 and 2000AU. - Most disks are in Keplerian rotation. - Temperature structure consistent with flared disk models and T at CO disk surface ( =1) goes like T(r) ~ r -0.6. - Vertical temperature gradients with cooler disk mid-plane. - Disk temperature increase with increasing central stellar mass. - Beyond 150AU, disks around low-mass stars have T<17K, therefore, CO can freeze out on dusk grains.
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Inner disk regions Squares: gaseous inner disk radii (CO fundamental) Circles: dust inner disk radii (interferometry and SEDs) - Mid-infrared emission lines of vibrationally excited CO traces gas > 1000K. - The gas rotates at Keplerian velocity --> line-widths converts to inner disk radii. - Inner gas disk extends beyond disk sublimation radius and is close to co-rotation radius (coupling of stellar magnetic field to disk). Najita et al. 2007
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Disks in massive star formation IRAS20126+4104, Cesaroni et al. 1997, 1997, 2005 Keplerians disk around central protostar of ~7M sun - Still deeply embedded, large distances, clustered environment --> confusion - Current obs. status largely “Velocity gradient perpendicular to outflow”. - (Sub)mm interferometry important to disentangle the spatial confusion. - The right spectral line tracer still missing which can distinguish the disk emission from the surrounding envelope emission. IRAS18089-1732 Beuther & Walsh Hot rotating structure not in Keplerian motion.
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Summary Bergin et al. 2006
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Star and Planet Formation Sommer term 2007 Henrik Beuther & Sebastian Wolf 16.4 Introduction (H.B. & S.W.) 23.4 Physical processes, heating and cooling, radiation transfer (H.B.) 30.4 Gravitational collapse & early protostellar evolution I (H.B.) 07.5 Gravitational collapse & early protostellar evolution II (H.B.) 14.5 Protostellar and pre-main sequence evolution (H.B.) 21.5 Outflows and jets (H.B.) 28.5 Pfingsten (no lecture) 04.6 Clusters, the initial mass function (IMF), massive star formation (H.B.) 11.6 Protoplanetary disks: Observations + models I (S.W.) 18.6 Gas in disks, molecules, chemistry, keplerian motions (H.B.) 25.6 Protoplanetary disks: Observations + models II (S.W.) 02.7 Accretion, transport processes, local structure and stability (S.W.) 09.7 Planet formation scenarios (S.W.) 16.7 Extrasolar planets: Searching for other worlds (S.W.) 23.7 Summary and open questions (H.B. & S.W.) More Information and the current lecture files: http://www.mpia.de/homes/beuther/lecture_ss07.htmlhttp://www.mpia.de/homes/beuther/lecture_ss07.html and http://www.mpia.de/homes/swolf/vorlesung/sommer2007.htmlhttp://www.mpia.de/homes/swolf/vorlesung/sommer2007.html Emails: beuther@mpia.de, swolf@mpia.de
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