Star and Planet Formation

1
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.html

and http//www.mpia.de/homes
/swolf/vorlesung/sommer2007.html
Emails beuther_at_mpia.de, swolf_at_mpia.de
2
Accretion disks
3
Simple case flat, black disk
Beckwith et al. 1996, 1999
4
Effects of gaps on disk SED
Full line no gapLong-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.
5
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 --gt Disk flaring

6
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
Evert, grav h/r GM/r
Etherm kT(r) with T(r) r-3/4
--gt h k/GM r5/4
7
Hydrostatic equilibrium, radiative transfer
models for flared disks I
Chiang Goldreich 1997
8
Hydrostatic equilibrium , radiative transfer
models for flared disks II
nvert exp(z2/2h2)
h
Chiang Goldreich 1997
9
Hydrostatic equlibrium, radiative transfer
models for flared disks III
Chiang Goldreich 1997
10
Flat spectrum disks

• 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 --gt 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)
13
Disk dynamics Keplerian motion
For a Keplerian supported disk, centrifugal
force should equal grav. force. Fcen
mv2/r Fgrav Gmm/r2 --gt v (Gm/r)1/2
14
Non-Keplerian motion AB Aur

• Central depression in
• cold dust and gas
• emission.
• Non-Keplerian velo-
• city profile vµr -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).

PdBI, Pietu et al. 2005
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Disk-jet co-rotation in DG Tau
Testi et al. 2002
Corotation of disk and jet
Bacciotti et al. 2002
16
Disk structure
Pietu et al. 2007
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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 (t1) 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
  Tlt17K, therefore, CO
• can freeze out on dusk grains.

18
Inner disk regions
Squares gaseous inner disk radii (CO
fundamental) Circles dust inner disk radii
(interferometry and SEDs)
Najita et al. 2007

• - Mid-infrared emission lines of vibrationally
  excited CO traces gas gt 1000K.
• The gas rotates at Keplerian velocity --gt
  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).

19
Disks in massive star formation
IRAS18089-1732 Beuther Walsh Hot rotating
structure not in Keplerian motion.
IRAS201264104, Cesaroni et al. 1997, 1997,
2005 Keplerians disk around central protostar of
7Msun

• Still deeply embedded, large distances,
  clustered environment --gt 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.

20
Summary
Bergin et al. 2006
21
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.html

and http//www.mpia.de/homes
/swolf/vorlesung/sommer2007.html
Emails beuther_at_mpia.de, swolf_at_mpia.de