John Bally - PowerPoint PPT Presentation

Loading...

PPT – John Bally PowerPoint presentation | free to download - id: 13a5ce-YjMwZ



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

John Bally

Description:

John Bally – PowerPoint PPT presentation

Number of Views:52
Avg rating:3.0/5.0
Slides: 152
Provided by: johnb225
Learn more at: http://www.ipam.ucla.edu
Category:
Tags: bally | bol | john

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: John Bally


1
Star Formation
John Bally

Center for Astrobiology
Center for Astrophysics and Space Astronomy
Department of Astrophysical
and Planetary Sciences University
of Colorado, Boulder
2
  • Outline
  • Introduction to Stars Star Formation
  • Molecular Clouds
  • Formation of Isolated Low-Mass Stars
  • - Gravitational collapse
  • - Rotation, magnetic fields
  • - Disks
  • - Jets and outflows
  • Multiples, Clusters, Associations
  • - The Galactic Ecology
  • Impact of Massive Stars
  • Massive Star Formation
  • Birth of Planetary Systems
  • Metallicity Effects
  • Star Formation in the Early Universe

3
Introduction to Stars Star Formation
Stars The fundamental building blocks of the
Universe
High mass (8 - 100 x Mass of Sun)
Sources of light, chemical elements
Short lived lt 1 to 30 x 106 years
Luminous 103 - 106 x LSun
Source of energy in interstellar medium
Intermediate Mass (2 lt 8 x Mass of Sun)
Low Mass (lt 2 x Mass of Sun)
Long Lived gt 109 years
(Lock up mass for long
time)

Planets Abodes of life
Faint lt 0.001 - 10 x LSun
4
60M
106
Hertzsprung- Russell diagram
10M
107 yrs
Live Fast Die Young Lifetime t(100 Mo )
3 Myr t(10 Mo ) 30 Myr t(1 Mo ) 10
Gyr t(0.1 Mo ) 100 Gyr
108yrs
1M
109 yrs
1
1010yrs
1011 yrs
0.1M
10-5
5
Evolution of Stars
Very massive star (M gt 60 Sun) live few million
years very hot, luminous main-sequence
star powerful stellar winds, mass loss
blue super-giant
luminous blue variable, Wolf-Rayet star
type Ib,c supernova
black hole Massive stars (60gtM gt 8 Sun)
live 3 to 30 million years hot, luminous
main-sequence stars stellar winds
red super-giant ? blue
super-giant type II supernova
neutron stars / pulsar Low
to moderate mass stars (M lt 8 Sun) live
30 million to gt 14 billion years red
giant gt planetary nebula gt white dwarf

6
Introduction to Star Formation
Shrink size by 107 increase density by x 1021 !
Where planets also form
  • Giant Molecular Clouds (GMCs)

Raw material for star birth
  • Gravitational Collapse Fragmentation

Proto-stars, proto-binaries, proto-clusters
  • Rotation Magnetic Fields

Accretion disks, jets, outflows
7
  • The Ingredients
  • Gas
  • - H2, HI, HII, CO, CS, H2O, HCO, N2H,
  • Dust
  • - 0.01 1 mm grains silicates, graphite,
    ices
  • EM Radiation
  • - IR, visual, FUV, EUV, X-ray
  • Magnetic fields
  • - 10 1,000 m gauss
  • Cosmic Rays
  • - 1 MeV gt 1021 eV

8
Rho Ophiuchus (visible)
9
Rho Ophiuchus (850 microns)
Johnstone et al. (2004)
10
HH 46/47
11
BHR 71
12

Star-forming region
150 young stars Forming in Cygnus
S106 Subaru Observatory
13
The Circinus Cloud
14
A young Cluster NGC 3603 50 O stars 104
Low-mass stars
15
Large Magellanic Clouds D 50
kpc Irregular galaxy

16
M51 D 3.8 Mpc Grand Design spiral galaxy

17
M81
18
M83 D 3 Mpc Nulcear Star-burst Interaction W
ith M81 NGC3077
19
Colliding galaxies The Antennae (Hubble) -
Galaxy collisions trigger birth of stars,
star clusters, super-massive black holes
20
Giant Molecular Clouds
The Raw Material of Star and Planet Formation
  • Massive M 103 to 106 x MSun
  • Molecular H2
    (70)
  • He
    (29)
  • Trace Molecules
    (1)
  • CO, OH, CS, HCO,
  • organics, ,
  • Cold T 5 to 50 K
  • Dense n(H2) 100 to gt 105 cm-3
  • Giant L 10 to 100 light
    years

21
NGC 1333
Barnard 5
IC 348
Barnard 1
IRAS 032353004
22
Orion A
12CO 230 GHz 1.3 mm
23
Orion A
13CO 220 GHz 1.3 mm
24
Clouds are turbulent Mach 10 to gt100
25
Gravitational Condensation
Shrink size by 107 increase density by x 1021 !
Giant Molecular Cloud
Star Forming Cloud Core
Group of Stars
  • Cores Disrupted After Converting 5 to 20
  • of their Mass into Stars Disruption by
  • Outflows,
  • UV radiation (Massive Stars)

26
  • Star Formation in Molecular Clouds
  • Classical dynamical theory (Jeans Mass)
  • Vescape (2GM / r )1/2 gt (kT / mmH)1/2 Cs
  • Magnetic fields, rotation, turbulence (Shu)
  • - Core disk
    protostar
  • Turbulent collapse (Klessen, McLow, Padoan)
  • - Transient density enhancements in wave-field
  • Compression-Induced Collapse
  • - Anisotropic, chaotic motion

27
Giant Molecular Cloud
Star Forming Core
Accretion Disks Proto-Stars
28
Isolated Low-Mass Star Formation Gravitational
Collapse, Spin, Magnetic Fields
Gravity
Disks
Rotating Core
Jets
29
Time Mass Scales (for nH 105 cm-3,
T 10 K) Jeans Length rJ
(3k/8pmmHG)1/2 T1/2r-1/2 1017
cm Jeans Mass MJ (3/4p)1/2(k/2mmHG)3
/2 T3/2r-1/2 3 x 1032 grams 0.16
Mo A convenient starting point Isothermal
spheres r(r) r0
r-2 Accretion rate dM/dt c3 / G
4 x 10-6 (Moyr -1) t
(Gr) -1/2 2.5 x 105 yr
30
velocity
density
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
A young star Accretion controlled by magnetic
fields funnel flows
35
(No Transcript)
36
Outflows HH objects, H2, CO
Terminal working surface
Internal working surfaces
HH jet (high V)
H2 (moderate V)
CO outflow (low V)
37
L1551 SII
38
L1551 SII
39
L1551
CO J2-1
6-7 km/s
8-12 km/s
1-5 km/s
40
L1551
SII with CO
41
The Carina Nebula
The Carina Nebula (CTIO Schmidt)
42
HH 666
O III Ha S II
120 arcsec
43
HH 666
30 arcsec
O III Ha S II
44
HH 666
4.5 3 pc
O III Ha S II
45
HH 666
S II
Ha
46
J H K
HH 666
Pab Fe II H2
47
HH 3
NGC 1999
New jet
HH 1
HH 2
proplyd
48

HH 2
HH 1
HST 1997 - 1994
49
HH 2
HH 1
HST 1997 - 1994
50
HH 1 jet
HST 1997 - 1994
51
HH 1 jet
HST 1997 - 1994
52
HH 1
HST 1997 - 1994
53
HH 1
HST 1997 - 1994
54
HH 2
HST 1997 - 1994
55
HH 2
HST 1997 - 1994
56
HH 46/47
HST 1997 - 1994
57
HH 46/47
HST 1997 - 1994
58
HH 34
HST 1997 - 1994
59
HH 34
HST 1997 - 1994
60
HH 34 parsec-scale flow
2.5 pc
61
NGC 1333 in Perseus 150 young stars
62
NGC 1333
HH 12
HH 7-11
63
Irradiated Jets
HH 333
HH 498
HH 499
HH 334
64
YSOs in isolated cometary clouds
IRAS 032353004 near L1455
65
Most Stars Form Near Massive Star Groups
  • GMCs Spawn 5,000 to 30,000 Stars
  • in a region less than 100 light years in
    diameter
  • Most low mass stars exposed to effects of high
  • mass stars during their youth
  • Most Proto-planetary Disks are irradiated
  • - UV removes H, He increase mid-plane metals
  • - gravity gt induced planetesimal formation

66
NGC 3603
67
Most Stars Form Near Massive Star Groups
  • GMCs Spawn 5,000 to 30,000 Stars
  • in a region less than 100 light years in
    diameter
  • in about 10 Myr
  • Within 600 pc of the Sun (t lt 15 Myr)
  • 3 OB associations 10 dark
    clouds
  • Sco/Cen, Per OB2, Orion Taurus, Lupus, .
  • 50,000 stars
    5,000 stars
  • Within Orion A (t lt 2 Myr)
  • 2,000 stars in Trapezium cluster, lt 300 in
    L1641
  • 90 of stars born near OB stars! Disk
    mortality.

68
Mass Spectrum of Giant Molecular Clouds (GMCs)
  • Most stars born in
  • GIANT molecular clouds!
  • Mass spectrum
  • gt gt 85 of H2 mass
  • in Galaxy is in
  • Mgt105 Mo clouds
  • Nearby young stars
  • (D lt 600 pc)
  • gt gt90 of stars
  • in OB associations
  • Most stars form in transient
  • clusters, near massive stars

Brand (1993)
Solomon et al. (1987)
69
500 pc
lt 10 Myr bubbles
Sun
30 - 50 Myr old Gould's Belt /Lindblad Ring
de Zeeauw et al.
70
(No Transcript)
71
Galactic Ecology Star Formation the
Interstellar Medium
72
The Orion Star Forming Complex
73
The Orion/Eridanus Bubble (Ha) d180 to 500pc
l gt 300 pc Orion OB1 Association 40 gt 8
M stars 20 SN in 10 Myr
l
Ori (lt 3 Myr)
1a (8 - 12 Myr d 350 pc))
1b (3 -6 Myr d 420 pc)
1c (2 - 6 Myr d 420 pc)
1d (lt2 Myr d 460 pc)
Eridanus Loop
Barnards's Loop
74
Orion Molecular Clouds 13
Orion B
2.6 mm
CO
Orion Nebula
Orion A
75
(No Transcript)
76
(No Transcript)
77
Infrared view of winter sky (10 - 120 mm)
78
(No Transcript)
79
Orion below the Belt
NGC 2024 (OB1 d)
Horsehead Nebula
s Orionis (OB 1 c)
NGC 1977 (OB1c)
Orion Nebula (OB1 d)
i Ori (OB 1c)
80
Orion Nebula
Distance 1,500 light years Age lt 1 million
years
Young stars 2000 low mass 10 high mass
Nearest massive star forming region
81
Orion Nebula
Near Infrared
82
d253-535 in M43
83
HH502 in Orion C-symmetric jet-sidewind
collision
Redshitfted bows
HH400 rim
Crossing flow
Proplyd jet
To q1C
Blueshifted bow jet cocoon
84
To q1C
HH505 in Orion jet-sidewind collision fronts
85
Outflows from OMC1-S (Ha MOS/FP on 3.5 m CFHT)
86
(No Transcript)
87
(No Transcript)
88
0.5 2.2 mm
104 AU
89
11.7 mm
90
Orion Nebula
Hidden Massive Protostar Produced explosion
1,000 ago
Near Infrared
91
OMC1 - 12 mm (Shuping et al. 2004)
NH3
H2O masers
Radio sources
92
OMC1 - 12 mm (Shuping et al. 2004)
NH3
93
OMC1 (Shuping et al. 2004)
NH3
94
OMC1 SiO J1-0 (Greenhill et al. 2004)
95
OMC1 SiO J1-0 7mm continuum (Greenhill
et al. 2004)
96
OMC1 SiO J1-0 (Greenhill et al. 2004)
97
OMC1 H2 fingers
98
Core of the Orion Nebula (Hubble Space Telescope)
99
(No Transcript)
100
Trapezium cluster
massive stars
Low mass stars
101
Disks in the Orion Nebula
D 1500 light years
  • Dozen high mass stars (Trapezium)
  • lt 100,000 years old
  • 2,000 low mass stars lt 1.5 million years old
  • - Out of 400 stars images with HST .
  • 15 Proto-Planetary Disks in silhouette
  • (Silhouette proplyds)
  • - Evidence for grain growth
  • gt 200 Evaporating Proto-Planetary Disks
  • (Bright proplyds)
  • - Evidence for disk destruction

102
Planet Formation
  • Agglomeration in the Accretion Disk
  • Laplace (1796),
  • Grain growth, Sedimentation, Coagulation
  • Planetisimals, Proto-Planets, Collisions,
  • Accretion

From micro-meters to meters lt 1 million years
From meters to 10s of kilometers 0.1 to 10
million years
  • Era of Bombardment, Planets Moons

From 1 to 10,000 km lt 500 million years
  • Gravitational Instability in a Disk
  • Boss (1998),

103
(No Transcript)
104
Taurus disks jets Stapelfeldt et al.
105
HST 16
HST 10
HST 17
Irradiated proto-planetary disks
106
Evaporating disks
182-413 (HST10)
107
Evaporating disks
108
Orion Nebula Disks seen in silhouette only
109
Tr14
Ha
Keyhole
Tr16
h Car
Ha
110
Proto-planetary disk candidates (proplyds) in
the Carina Nebula Luminosity 100 x Orion
Smith et al. (2003)
111
Disk Photo-ablation
EUV l lt 912 A (E gt 13.6 eV)
H gt H
heating by
electrons T 10,000
K cII 10 km/s FUV 912 A lt l lt 2,000 A
( 6 eV lt E lt 13.6 eV) heating by
dust photo-electrons, 2H gt H2
T 100 to 5,000 K cI 1 5
km/s Escape at r gt GM / c2 5 AU for
cII (for Solar mass)
40 AU for cI Self-irradiatio
n vs. External irradiation Lself(UV) / 4
p d2 Lexternal(UV) / 4 p dOB2 External
irradiation Lexternal(UV) 1049 photons /
sec Self - irradiation Lself(UV) 1040
- 1043 photons / sec
112
(No Transcript)
113
(No Transcript)
114
6 13.6 eV UV photons
115
6 13.6 eV UV photons
116
6 13.6 eV UV photons
117
6 13.6 eV UV photons
118
(No Transcript)
119
(No Transcript)
120
(No Transcript)
121
(No Transcript)
122
Stellar wind
123
Stellar wind
124
(No Transcript)
125
(No Transcript)
126
rG GM/c2 C 3 km/s
127
(No Transcript)
128
(No Transcript)
129
(No Transcript)
130
(No Transcript)
131
(No Transcript)
132
(No Transcript)
133
(No Transcript)
134
(No Transcript)
135
Impacts of the environment
  • Life of a massive star planet formation
    time-scale
  • Clustering, multiplicity Close-encounters
    with stars
  • - truncate, shock-heat disks
  • UV radiation External self-irradiation
  • - gain growth sedimentation
    photo-ablation
  • gt concentrate metals gt grav. Instability
    gt planetesimals
  • - UV doses
  • External main-sequence 1049 g
    sec-1 x (107 years)
  • blue-supergiant (lt 106 years)
    supernova (1 year)
  • Self-irradiation 1040 1044 g sec-1
  • Massive star winds and Supernovae
  • - implant short-lived isotopes 26Al, 60Fe

136
M 20 m 5 Mdisk 1
Close encounters
Moeckel Bally 04
137
Prograde
Retrograde
Moeckel Bally 05
Close encounters
138
Retrograde Shock heated layer
139
Prograde Shock heated layer
140
Star Formation in the Early Universe
  • Dark matter potential wells
  • T 2.73 (1z) 10 100 K
  • - Higher Jenans mass
  • - Proto-planetary disks observed
  • No metals H and He only
  • - Inefficient cooling
  • - Inefficient fragmentation
  • - Hotter, more compact stars
  • No magnetic fields

141
Cosmic Microwave Background mm wavelengths
A glimpse at the Universe 300,000 years after the
Big Bang (13.7 billion years ago)
Smooth to 1 part per 100,000!
142
Cosmic Microwave Background t 300,000 yr, z
1000 Proto-galactic clouds t 100 Myr,
z 100 First stars (Pop III) t 300 Myr,
z 30 Proto-galaxy merging t gt 1 Gyr,
z lt 10 Modern Universe t gt 5 Gyr
z lt 2

143
Conclusions Topics for simulations
  • Turbulent Collapse
  • Anisoptropic / shock-induced (HII, SN,
    superbubbles?)
  • Fragmentation gt Transient clusters / multiple
    systems
  • Effects of magnetic fields
  • Massive star formation accretion or merging?
  • Bound cluster formation
  • Run-away star formation AGN?
  • Jet launch/collimation
  • UV photoablation
  • Star formation at low-metallicity
  • Planet formation
  • Feedback
  • Cloud formation/destruction

144
The End
145
(No Transcript)
146
(No Transcript)
147
(No Transcript)
148
(No Transcript)
149
(No Transcript)
150
(No Transcript)
151
(No Transcript)
About PowerShow.com