初期銀河ハロー質量関数と ç‚­ç´ éŽå‰°è¶ é‡‘å±žæ¬ ä¹æ˜Ÿ 概要 - VERA - 国立 ...

♦
EMP star
–
♦
(CEMP star)
–
•
probe
•
– EMP star
–EMP star
•
•
IMF

♦
♦
CEMP starsBinary Scenario
1. CEMP stars EMP stars
2.
3.
CEMP stars
1. CEMP stars
2.
IMF
3.
CEMP stars
([Fe/H]2.5)

C, N, S-process
C: open
N: filled
S-process
(
)
(CEMP-s)
(CEMP-nos)
2
CEMP-s N
C
CEMP-nos N
C
10
N-rich star
(N/C~10)
S-process
(Busso et al.1999)
[Fe/H]~-2.5
s-process
S-process

Binary Scenario
C
CEMP stars
C
C
C
C C C
He flash
C
C
AGB
C
C
CEMP star
Binary Scenario
♦
–CH star s-process Popstar
– CEMP star
(Lucattelo et al.2005)
–
giant
dwafr
•
[C/H]
( CEMP-s
CEMP-nos
-3 -2 -1 0 [C/H]
[Fe/H]

EMP star
[Fe/H]
-2.5
-4
0.8~3.5M CEMP-s
CEMP-s
He-FDDM
TDU
(s-process )
CEMP-nos
TDU
(s-process )
N-rich
Z=0
0.8 1.2 1.5 3.5 6 (M )
3.5~6M CEMP-nos
He-FDDMC,N
flash driven deep
Third Dredge UpC
(TDU)
mixing s-process
(He-FDDM) s-process
1.5~3.5M TDU5M
CN
N C
♦

Binary Scenario
♦ [C/H]
[C/H]=0wind
Giant Dwarf
1.5M
3M 0.3M
Jeans
giant
Sub giant
Dwarf
[C/H]
Binary Scenario
CN
C
s-process
CEMP
• C
•
C
RLO
M

Binary Scenario
Binary Scenario
CEMP
CEMP-s
CEMP-nos
N rich star
0.5~100AU
0.8~6M
(3.5:CEMP-nos
>5M :N rich)
M CEMP star
♦
(HK survey, HES survey )
1. EMP star 310 5 2. 20~25%CEMP
3. CEMP1/3~1/4CEMP-nos
♦
N-rich CEMP-nos

CEMP star
♦
–
: ( review by Chabrier et al.2003)
−1.35
ξ log m ∝ m m>
0.8M
( )
2
⎛ log m − log 0.22 ⎞
∝exp − : m<
0.8M
2
⎜ 2 0.33 ⎟
⎝
×
⎠
– (Duquennoy
& Mayer 1991)
f
⎛
log ( ) ∝ exp
−
⎜
⎝
( P day )
( log P − 4.8) 2
2×
2.3
–
( ) = const.
n q
( )
(q=M 2 /M 1 )
2
⎞
⎟
⎠
Distribution of mass ratio
(Abt 1983)
B-type star
G-dwarf (Duquennoy & Mayer 1991)

IMF
♦
IMF
CEMP-s
–
0.8 3.5 n( M2 / M1)
AM
( M1)
CEMP− s
= ∫ 2 s ( ( 2)
) ξ( 1)
1
0.08 ∫0.8
∫A
M
ψ
ψ
CEMP nos
dM N L M M dM f ( A)
dA
M
He−FDDM
( 1)
14%
CEMP-nos
0.8 6 n( M2 / M1)
−
= ∫ 2 s ( ( 2)
) ξ( 1)
1
0.08 ∫3.5
∫
1
( M )
AM
1
dM N L M M dM f ( A)
dA
M
ATDU
( M1)
1
0.3%
IMF
IMF
–Lo normal IMF
2
⎛ (log m−
log M )
( log ) exp
c
⎞
ξ m ∝ ⎜−
2 ⎟
⎝ 2×
σ ⎠
CEMP − nos
CEMP − s
CEMP-s
CEMP-nos
Mc
0.2 0.5 1 2 5 10 20 (M )
Mc
CEMP-s
~1M ~10M 2
10M
CEMP star
CEMP-nos

IMF
CEMP-s
CEMP-nos
nos
Mc
Mc=10M ,=0.4
IMF
CEMP
EMP star
r-process
-1 0 1 2
Log(m)

10 9 10 7 10 8
EMP
EMP star
310 5
Mc
EMP star
10 7 , 10 8 ,10 9 M
~10 8 M
[Fe/H]~-3
10 7 10 8 M
10 6 M
[Fe/H]~-2
EMPstar
Black Hole

♦ EMP
– 10%EPM
– CEMP-s, CEMP-nos: 22~40% WD
–SN : 60~40% ( )
r-process
♦ EMP 310 5
10 7
10 8 M
♦ [Fe/H]~-2.5IMF
c.f.,
[Fe/H] > -2.5
Conclusions
♦ CEMP star Binary scenario
–
♦
–
–
♦ ([Fe/H]

Period distribution
(Duquennoy & Mayer 1991)
Lognormal
I II
He-flash
Third dredge-up
radiative C α,n) 16 O burning
convective
overshooting
extra mixing
13
C pocket

: I II
♦ Third dredge up
Third dredge up
S-process
convective overshooting
radiative C α,n) 16 O burning
He
shell flash
13
C
S-process
C( )
S-process
[C/H] : CH star
Giant
[C/H]~0.5wind
Dwarf
CH stars
CEMP

CH stars &
s-process elements
S-process
CEMP-nos
Sr,Y,Zr
Ba-Sm
CH-star
Low mass dwarf

Various trends and scatters in the abundances
with metallicity
α

EMP star
[Fe/H]
-2.5
TDU
(s-process )
-4
He-FDDM
TDU
(s-process )
Z=0
0.8 1.2 1.5 3.5 6 (M )
2
He-Flash Driven Deep MixngThird Dredge Up
:
♦ 0.8~3.5M
He flash driven deep mixing
– He shell flash
–
C( )
N
He
12
C(p,) 13 N(e + ,) 13 C(,n) 16 O
S-process

:
(2)
:Third dredge up
EMP s-process
♦ 3.5~6M
♦ 5M
– Third dredge up
hot bottom burning
–CN
– N/C~10
(CN)
C
5M N
EMP star
♦ He flash driven deep mixing
– He core flash
– H shell flash
C( ) N
S-process

CEMP star
♦
CEMP star
CEMP star
AU
CEMP star
N rich stars
N/C=10

R-process
r-orocess
CEMP star
♦
Pop
CEMP
1.5
( )
( / M )
3.5 n M
A
2 1
MCEMP , ( M1)
( M1)
dM1
f( A)
dA
NCEMP ( ) ∫ ξ
0.8 M
∫A
He−FDDM
( M1)
1
= = 14
NCHstar ( ) 5 n( M / M )
( M )
ξ M dM f( A)
dA
∫
2 1
1 1
M1
∫
AMCH
, 1
ATDU
( M1)
f(A)
n(q)
(m) IMF
EMP star CEMP-s
Popstar CH star 14

CEMP star
♦ GiantDwarf
–CEMP star
n(q)
IMF
–GiantDwarf
Binary Sbenario
Giant : Sub giant : Dwarf 26: 4: 4
63% : 10% : 27%
(76% : 12% : 12%)