[PPT] - S t a r F o r m a t i o n i n T u r b u l e n PowerPoint Presentation

SLIDE 1

S t a r F

r

m a t i

n

i n T u r b u l e n t , M a g n e t i z e d C l

u

d s

F u m i t a k a N a k a m u r a ( N i i g a t a U n i v e r s i t y ) Z h i

Y

u nL i ( U n i v e r s i t y

f

V i r g i n i a )

SLIDE 2

P r

p

e r t i e s

f

M

l

e c u l a r C l

u

d s

S

u p e r s

n

i c t u r b u l e n c e m

l

e c u l a r c l

u

d i s h i g h l y t u r b u l e n t . l i n e w i d t hδV i s l a r g e r t h a n C s .

S

t r

n

g m a g n e t i c f i e l d

b

s e r v e d B f i e l d i s c l

s

e t

a

c r i t i c a l v a l u e .

c r i t i c a l m a s s s u p e r c r i t i c a l v s . s u b c r i t i c a l ↓ q u a s i

s

t a t i c c

n

t r a c t i

n

d u e t

a

m b i p

l

a r d i f f u s i

n

flux magnetic = Φ Φ = , 13 .

2 / 1

G M cr

Supercritical Subcritical H e i l e s& C r u t c h e r 2 2

cr

M M >

cr

M M <

SLIDE 3

１．G a l a c t i c S t a r F

r

m a t i

n

D i s p e r s e d m

d

e ： l

w
m

a s s s t a r s T a u r u s l

w

S F E ( a f e w % ) M a g n e t i c a l l y

r

e g u l a t e d m

d

e l ( a m b i p

l

a r d i f f u s i

n

, i n s i d e

u

t ) (

S h u , A d a m s , L i z a n

1

9 8 7

) T u r b u l e n c e

a

c c e l e r a t e d , m a g n e t i c a l l y r e g u l a t e d s t a r f

r

m a t i

n

(

L i & N a k a m u r a 2 4 ; N a k a m u r a & L i 2 5

） C l u s t e r m

d

e ： m a s s i v e a n d l

w
m

a s s s t a r s O r i

n

h i g h S F E ( 1

2

% ) S t r

n

g s u p e r s

n

i c t u r b u l e n c e S t r

n

g m a g n e t i c f i e l d （C r u t c h e r 2 5 ） F e e d b a c k f r

m

y

u

n g s t a r s （B a l l y e t a l . 1 9 9 9 ）

SLIDE 4

２．T u r b u l e n c e s i m u l a t i

n

s

O

b s e r v a t i

n

s

f

c l u s t e r f

r

m i n g r e g i

n

s

I m p

r

t a n c e

f

p r

t
s

t e l l a r

u

t f l

w

s （C i r c i n u sc

m

p l e x B a l l y e t a l . 1 9 9 9 ; N G C 1 3 3 3 Q u i l l e ne t a l . 2 5 ; s e e a l s

N
r

m a n & S i l k 1 9 8 )

H

D T u r b u l e n t s i m u l a t i

n

s

( K l e s s e ne t a l . 1 9 9 8 ; B a t e e t a l . 2 3 )

S i n k p a r t i c l e , b u t n

p

r

t
s

t e l l a r

u

t f l

w

s

M

H D T u r b u l e n t s i m u l a t i

n

s

T i l l e y & P u d r i t z 2 5 , S u g i m

t
&

H a n a w a 2 4 )

p r i

r

t

s

t a r f

r

m a t i

n

Q u i l l e ne t a l . ( 2 5 ) E f f e c t

f
u

t f l

w

s （N G C 1 3 3 3 ）

SLIDE 5

3 . O u r s i m u l a t i

n

s

P

r e v i

u

s n u m e r i c a l s i m u l a t i

n

s h a v e n ’t t a k e n i n t

a

c c

u

n t t h e e f f e c t

f

s t e l l a r f e e d b a c k .

W

e i n c l u d e s e l f

g

r a v i t y , s u p e r s

n

i c t u r b u l e n c e , m a g n e t i c f i e l d , a n d p r

t
s

t e l l a r

u

t f l

w

. 3 D M H D t u r b u l e n t s i m u l a t i

n

s

SLIDE 6

Q u e s t i

n

s

W

h a t d e t e r m i n e s t h e e f f i c i e n c y

f

s t a r f

r

m a t i

n

? m a g n e t i c f i e l d , p r

t
s

t e l l a r

u

t f l

w

H

w

i s t u r b u l e n c e m a i n t a i n e d i n c l u s t e r f

r

m i n g c l u m p s ? p r

t
s

t e l l a r

u

t f l

w

SLIDE 7

４. M

d

e l

I

s

t

h e r m a l s p h e r i c a l c l

u

d

U

n i f

r

m m a g n e t i c f i e l d ( s u p e r c r i t i c a l )

S

u p e r s

n

i c v e l

c

i t y f i e l d （L a r s

n

’s l a w ） (

)

n k

k E

−

∝

1 pc = 9LJ

Effective radius = 1.5LJ

LJ= thermal Jeans length

5 . 2 112 = = α µ

for

G Bx

S

t a r f

r

m a t i

n

a n d p r

t
s

t e l a l r

u

t f l

w

s

3

128 @ 100 ρ ρ =

cr

3 4 2

11 . 20 10 1 . 6

−

⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × = cm pc

J H

L K T n pc pc ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ≈ = 11 . 1 9

J J

L L L pc ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = 11 . 20 626

J

L K T M M

G

pc µ α ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ =

J / x

L K T B 11 . 20 71

2 1

0.17 pc

SLIDE 8

５. E f f e c t

f

M a g n e t i c F i e l d : N

u

t f l

w

α = 2.5, M = 10

２３１１２３ D i r e c t i

n
f

i n i t i a l B f i e l d D i r e c t i

n
f

i n i t i a l B f i e l d

c

l

u m n d e n s i t y

K T M M G B L nH 20 , 626 , 111 99 . , 10 1 . 6

3 4 , 2

= = = = × =

−

pc cm

µ

SLIDE 9

S t a r F

r

m a t i

n

E f f i c i e n c y

I

n t h e a b s e n c e

f

m a g n e t i c f i e l d , t h e S F E b e c

m

e s t

h

i g h .

M

a g n e t i c f i e l d c a n r e d u c e t h e S F E .

N

T

N

B

T N

B

T B S t r

n

g e r B

100 ) ( ρ ρ ρ ρ = ≥ =

cr tot cr

M M SFE

SLIDE 10

S u m m a r y 1

T

h e i n i t i a l t u r b u l e n c e d e c a y s q u i c k l y . I t i s d i f f i c u l t t

m

a i n t a i n s u p e r s

n

i c t u r b u l e n t m

t

i

n

s .

M

a g n e t i c f i e l d i s n e e d e d t

r

e d u c e t h e S F E t h a t i s c

n

s i s t e n t w i t h

b

s e r v a t i

n

s ( 1 – 2 % ) .

T

h e c l

u

d t e n d s t

c
l

l a p s e i n t

a

s i n g l e d e n s e c

r

e n e a r t h e c e n t e r .

SLIDE 11

C

r e a t i

n
f

“s t a r s ”

P

r

t
s

t e l l a r

u

t f l

w

( M a t z n e r & M c K e e 2 ; N a k a m u r a & L i 2 5 )

6 ．E f f e c t

f

S t e l l a r O u t f l

w

1

s km

−

= = f M V M P

star W W

utflow

100 f :

u

t f l

w

s t r e n g t h

★ C i r c i n u sc

m

p l e x f ～ 0 . 3 ( B a l l y e t a l . 1 9 9 9 ) ★ X

w

i n d m

d

e l f ～ 1 / 3 ( S h ue t a l . 2 )

4 . 3 . ~ − f

★ M a t z n e r & M c K e e m

d

e l f ～ 0 . 4 ★ L 1 5 5 1 I R S 5 f = . 2 3 ～ 0 . 3 9 ★ L 1 1 5 7 f ～ 0 . 3

2 . ≈ = = > ε ε ρ ρ ρ

100 For

core star cr

M M

SLIDE 12

E f f e c t

f

O u t f l

w

２３１１２３ D i r e c t i

n
f

i n i t i a l B f i e l d D i r e c t i

n
f

i n i t i a l B f i e l d

C

l

u m n d e n s i t y

K T M M G B L nH 20 , 626 , 111 99 . , 10 1 . 6

3 4 , 2

= = = = × =

−

pc cm

µ

α = 2.5, M = 10, f = 0.5

1

s km

−

= = f M V M P

star W W

utflow

100

SLIDE 13

S t a r F

r

m a t i

n

E f f i c i e n c y

O

u t f l

w

r e g u l a t e s S F E s .

1

s km

−

= = f M V M P

star W W

utflow

100

SLIDE 14

7 . T u r b u l e n c e G e n e r a t i

n

I

n i t i a l t u r b u l e n c e d e c a y s q u i c k l y .

O

u t f l

w

s c a n g e n e r a t e a n d m a i n t a i n t u r b u l e n c e a t a l e v e l

f

M a c h 5 ( 1 – 1 . 5 k m s

1

) .

SLIDE 15

8 . S u m m a r y

B

t

h m a g n e t i c f i e l d a n d p r

t
s

t e l l a r

u

t f l

w

a r e i m p

r

t a n t i n r e g u l a t i n g s t a r f

r

m a t i

n

i n c l u s t e r f

r

m i n g r e g i

n

s .

T

u r b u l e n c e c a n b e g e n e r a t e d a n d m a i n t a i n e d b y p r

t
s

t e l l a r

u

t f l

w

s .

T

h e c

r

e m a s s f u n c t i

n

( t h e s t e l l a r I M F ) m a y b e d e t e r m i n e d b y s t a r s t h e m s e l v e s t h r

u

g h p r

t
s

t e l l a r

u

t f l

w

s , i n s t e a d

f

i n i t i a l t u r b u l e n t f i e l d .

P a d

a

n& N

r

d l a n d( 2 2 )