Transcript 23.4 Physical processes, heating and cooling … (HB)

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 … (H.B.)
30.4 Gravitational collapse & early protostellar evolution I (H.B.)
07.5 Gravitational collapse & early protostellar evolution II (H.B.)
14.5 Outflows and jets (H.B.)
21.5 Pre-main sequence evolution, stellar birthline (S.W.)
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: [email protected], [email protected]
M51: The Whirlpool Galaxy
M51: The Whirlpool Galaxy
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Andromeda
CO(2-1)
Optical
Mid-Infared view of part of Galactic plane
Giant Molecular Clouds
Sizes: 20 to 100pc; Masses: 104 to 106 Msun; Temperatures: 10 to 15K
Superesonic velocity dispersion ~2-3 km/s mainly due to turbulence
Magnetic field strengths of the order 10mG
Average local densities ~104cm-3; Volume-averaged densities ~102cm-3
--> highly clumped material
Sites of Star Formation
Masses:
Between fractions and a
few 100 solar masses
Optical
Near-Infrared
Densities:
Of the order 106cm-3
1.2 mm Dust Continuum
C18O
N2H+
Properties of Molecular Clouds
Type
n
Size
[cm-3] [pc]
T
[K]
Mass
[Msun]
Giant Molecular Cloud
102
50
15
105
Dark Cloud Complex
5x102
10
10
104
Individual Dark Cloud
103
2
10
30
Dense low-mass cores
104
0.1
10
10
Dense high-mass cores
>105
0.1-1
10-30
100-1000
Orion
The Star-Forming Region W43
Optical
Near-Infrared
1.2mm dust cont.
Planck's Black Body
Planck's Black Body
Wien's Law
max = 2.9/T [mm]
Examples:
The Sun
Humans
Molecular Clouds
Cosmic Background
T 6000 K  max= 480 nm (optical)
T 310 K  max= 9.4 mm (MIR)
T 20 K  max= 145 mm (FIR/submm)
T 2.7 K  max= 1.1 mm (mm)
Properties of Main Sequence Stars
Mass
[Msun]
60
40
20
10
4
2
1
0.8
0.2
Sp. Type
O5
O6
O9
B2
B8
A5
G2
K0
M5
Lum
[log(Lsun)]
5.90
5.62
4.99
3.76
2.26
1.15
0.04
-0.55
-2.05
Teff
[log(K)]
4.65
4.61
4.52
4.34
4.08
3.91
3.77
3.66
3.52
tMS
[yr]
3.4x106
4.3x106
8.1x106
2.6x107
1.6x108
1.1x109
1.0x1010
2.5x1010
>1011
tMS ~ 5x10-4 Mc2/L = 1x1010 (M[Msun])/(L[Lsun]) yr
} greater
than age of
universe
Number of Stellar Types in the Milky Way
80%
68%
Number
60%
The easiest to see
in night sky and
distant galaxies
40%
Sun
20%
13%
0%
1%
0%
0%
1%
O-M
F-M
O
B
A
3%
9%
7%
0%
Supergiant Red Giant
(I & II)
(III)
F
Main Sequence (V)
G
K
M
B-F
White
Dwarf
Star Formation Paradigm
Gas giants
Sizes not to scale
Jupiter
Saturn
Uranus
Mercury
Terrestrial
planets
Venus
Neptun
Earth
Mars
since 1995:
> 200 Extrasolar Planets discovered
• “Hot Jupiters”
• High masses
• Highly elliptical orbits
L.R.Cook
Overview planet formation (S.W.)
1. Introduction: Stars – Disks – Planets
2. Protoplanetary Disks: Observations
3. Disk models
1. Accretion, Transport Processes
2. Local Structure and Stability
4. Planet Formation Scenarios
5. Extrasolar Planets
The solar system: some striking facts
Planetary orbits are coplanar
Planets orbit the sun in the same direction
Distribution of Mass and Angular Momentum:
Sun Mass: 99.86% but Angular Momentum <2%
Age estimation: Sun and Planets have been formed at the same time
Extrasolar Planets:
large masses, high excentricities, low orbits
Immanuel Kant
“Allgemeine Naturgeschichte und Theorie des Himmels” (1755)
Solar System is evolving
Planets are formed from rotating gas disks
Star Formation – Planet Formation
Protostellar / Young circumstellar / Protoplanetary Disk:
- Gas / Dust disks around protostars
- typical diameter: a few 100 AU
Planet Formation: “Byproduct” of Star formation:
Collapse of a rotating molecular cloud core
(angular momentum <> 0)
=> Formation of a rotating distribution of the
infalling material around the central object
(Protostar / Pre-main-sequence Star)
Circumstellar Disks
- “Reservoir” for mass and angular momentum
- Environment + Material for Planet Formation
- Evolve in time (structure + composition)
McCaughrean et al. 1996
IRAS 04302+2247
betaPic
HK Tau
Young Circumstellar Disks
[ => Planet Formation ]
=> Debris Disks
BD+31643
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 … (H.B.)
30.4 Gravitational collapse & early protostellar evolution I (H.B.)
07.5 Gravitational collapse & early protostellar evolution II (H.B.)
14.5 Outflows and jets (H.B.)
21.5 Pre-main sequence evolution, stellar birthline (S.W.)
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: [email protected], [email protected]