晩期型恒星とその活動 晩期型恒星の彩層・コロナ - NAOtakedayi/ss_phys/presentation/watanabe.pdf恒星と活動~彩層・コロナ~ 2 z恒星の磁気活動
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国 立 天 文 台
渡 邊 鉄 哉
晩期型恒星とその活動~晩期型恒星の彩層・コロナ~
恒星と活動~彩層・コロナ~
2
恒星の磁気活動
彩層:水素の電離と熱的分化K(CaII)線 (non-LTE line formation)
ウィルソン・バップ効果と彩層の尺度則
遷移層のエネルギー収支-輻射損失と熱伝導
コロナループの尺度則diagnostics via CR-model
自転速度と活動性
恒星の磁場・黒点
活動周期
恒星と活動~彩層・コロナ~
3
Linsky, SP, 1985, 100, 333
恒星の磁気活動
(i)コロナからのX線
(ii)コロナからのマイクロ波
(iii)彩層~コロナからの紫外線
(iv)恒星磁場
恒星と活動~彩層・コロナ~
4
Chromospheric Activity measured by MgII h+k lines
恒星と活動~彩層・コロナ~
5
Correlation:
Chromosphere
vs
corona
Ayres et al., 1981, ApJ, 247, 545.
恒星と活動~彩層・コロナ~
彩層
恒星と活動~彩層・コロナ~
7
enthalpy kinematicnalgravitatio
mechanical conductive radiative
; ; ;
; ; ;
0)(
k eg
mcr
ekgmcr
F
FF
FF
F
FFFFFF =+++++∇
at τc ~ 10-4 (Tmin), ΔT ~ 150K
ΔH/H ~ 16T3/Teff4ΔTτc ~1.5×10
-5
Chromosphere; (3-6) ×106 erg/cm2sec
→ ΔH/H ~(5-8)×10-5 erg/cm2sec
Energy Flux out of Stars
恒星と活動~彩層・コロナ~
8
恒星と活動~彩層・コロナ~
9
水素の電離 electron donner at Tmin ~metal
at Ttop~hydrogen
population levellower )/exp(~)(excitation lcollisiona )/exp(~)(
abundanceelement : strength collision :
)()(4
kTAgkTXf
AQ
gfNNQAdzdH
u
el
Heel
±−
=
ττ
ττπ
Radiative loss
恒星と活動~彩層・コロナ~
10
)1( 0 )1( 1
energy excitation 2n : )/(
)1ln(ln)2(ln)1(
~ ))(1(
ln2lnln
/cmrate lossenergy ;
2
2
3
>=
=+=
⎥⎦⎤
⎢⎣⎡ −−+−+
×±++
=
恒星と活動~彩層・コロナ~
11
(i) Ne ← metal
(ii) Ne ~ Np γ
恒星と活動~彩層・コロナ~
12Vernazza, Avrett, Loeser: 1981, ApJS, 45, 635.
Empirical Chromospheric Model
恒星と活動~彩層・コロナ~
13
A: dark point within a cell B: average cell center C: average quiet sun
D average network E: bright network F: very bright network element
F’: flare (Fontenla et al. 1990)….
恒星と活動~彩層・コロナ~
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Thermal Bifurcation (Ayres 1981, ApJ 224,1064.)coolant CO & heater/coolant H-
F=eco+eH- (=0; radiative equilibrium)4900K H- cooling
H+ heating
4000K
CO dissociate
2900K
F
T
2900
4000
4900
5×106 erg/cm2sec
恒星と活動~彩層・コロナ~
15
Two-level atom without continuum
[ ]1
2
3
12
4)(
−
⎥⎦
⎤⎢⎣
⎡−⎟⎟
⎠
⎞⎜⎜⎝
⎛=
−=
++−=
lu
ul
ullulu
ulu
ululuull
gngn
ch
BnBnAnS
hIBAnIBndzdI
ν
πνφμ
ν
νννν
radiative transfer
statistical equilibrium
( ) ( )ulululululul CdJBAnCdJBn ++=+ ∫∫ νφνφ νννν
恒星と活動~彩層・コロナ~
16
[ ]
'1' ,
1'
)1('1
'
εεεε
εεε
ενφ
ν
ννννν
+≡
⎟⎟⎠
⎞⎜⎜⎝
⎛−
≡
+−≡+
+=
−
∫
ul
kTh
lu
l
A
eC
BJBdJ
S
Two level atom w/o cont.
恒星と活動~彩層・コロナ~
17
等温でも吸収線ができる!Bν,ε; const case → S
恒星と活動~彩層・コロナ~
18
mean free path; lνphoton destruction probability; Pdthermalization depth; Λ
photon escape probability; Pe
1;for
)()(
)()( ;
~
11~
1
1
=
=
=Λ+
+=
∫∞
x
xe
de
ulul
uld
clu
x
dxxP
PPAC
CP
l
τ
φτ
ττ
χφχχ ννν
恒星と活動~彩層・コロナ~
17-jun-04 19
[ ]
22
2-
122
1 1
11)( Lorentz;
)( Voigt;
1 1)( Doppler;
2
2
εΛ~
xx
aΛ~dyay)(xeax
εΛ~ex
-y
x
+=
+−=
=
∫∞
∞
−
−
πφ
εππφ
πφ
line profile φ(x) → thermalization depth Λ
BSl ε=)0(source function at the surface
恒星と活動~彩層・コロナ~
october2007 20
Wilson-Bappu Effect
恒星と活動~彩層・コロナ~
october2007 21
恒星と活動~彩層・コロナ~
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Wilson & Bappu 1957, ApJ. 125, 661
恒星と活動~彩層・コロナ~
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CaIIH&K Line Formation
strong gfN-value collision dominant (Sν ≈ Bν to middle chromosphere)
K2; formed at the thermalizationdepth
Ayres (1979)
恒星と活動~彩層・コロナ~
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Wilson-Bappu Effect; Interpretation• Chromospheric Thickness• W0; Dopper control?• Inside K1, k1; optically thick in chromosphere• ← effect of radiative transfer• Ayres 1979, ApJ 228, 509
26~
6
26
224*
107~
/107~
~/ ,~
min. re temperatu:* ,~
±
±
×
×
eff
tot
effeffMgIIMgIItot
tot
TF
scmergF
TTFFF
mF
dmdF
◎
σ
恒星と活動~彩層・コロナ~
255.2~/
~
~
~
75.0~
~~~
11
21
474/1~4/1~4/1~
2/1
~
~
2/1*
2**
~
12/7~2/1~2/1~2/1~
*
*
~
*
**
*
*
kKk
effFe
Fe
ell
ell
effFe
eff
FeeH
TgFAA
A
mA
TgFAm
mgPTT
ATPCn
dmdF
dmdF
λλ
κλ
λκτ λ
ΔΔ
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛Δ
Δ
=
⎟⎠⎞
⎟⎠⎞
±−−
−Δ
±−−
−
(hydrostatic)
経験的
Lorentzian wing control of K1
(観測:太陽 ~ 2.3)
恒星と活動~彩層・コロナ~
26
恒星と活動~彩層・コロナ~
279.0~/
~
~~
~~
: /)(~
1~
)125(2/1
2/1~3/2~1
~
~
11
*
12/5~2/1~2/1~2/1~1
*
26~~
11~
Kk
effFe
Fe
elllc
tot
l
effFeeffl
ulull
llellclc
TgFAA
Am
mF
dmdFn
TgFAmTFn
AnmA
ΛΛ
±−−−
−
−−Λ
±−−
±
−Λ
−
ΔΔ
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
Ω≡Λ=≈
Λ
λλ
ξεκ
ξεεξκτ
ε(thermalization length)
Doppler velocity
chromosphere mean density
(観測:太陽 ~1)
恒星と活動~彩層・コロナ~
28
• W(K1), W(K2) ともg-1/4でスケールする• W(K2)~ξ1/2 でスケールする• W(K2) ↑ F↓, while W(K1)↑ F↑
←観測 ○solar plage
恒星と活動~彩層・コロナ~
遷移層・コロナ
恒星と活動~彩層・コロナ~
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遷移層のエネルギー収支-輻射損失と熱伝導
(corona) Hc = Rc + Cc(transition region) Htr + Cc = Rtr
Observation: Rtr ~ Cc → Htr ~ 0
恒星と活動~彩層・コロナ~
• Line intensity of a permitted line (j → i)
)exp(
)()(
)(
)(
)(
)(
)(
)(
)(
)(
)(
2
02161063.8 kT
EaTC
XNNCXNCNNA
NNHN
HNXN
XNXN
XNXNN
NA
e
ij
i
ijeij
m
eijij
ij
m
ijejji
ee
m
m
m
jj
jjiij
ij
hc
hc
ΔΩ× −=
=
=
=
=
−−
+
+
+
+
+
πω
λλ
λλ
ε
ε
←radiative-collisional model
excited state
恒星と活動~彩層・コロナ~
32
TkTE
XNXN
TG
NHN
HNXNhc
NTG
e
eij
m
ei
ij
ij
eij
2/1
6
2
)/exp()()(
)(
)()()(
1063.8
)(
Δ−
=
Ω×=
+
−
=
ωλβ
βε
G(T); contribution function
↑ ion fraction
↓element abundance
恒星と活動~彩層・コロナ~
33
dSdTT
NTG
TdhdTdSdhdV
dVNTG
dVNTGI
e
em
e
∇=
∇≡=
=
=
∫∫∫
∫∫∫∫∫∫
1)(
l)(isotherma )(
)(
2
2
2
β
β
β
← differential emission measure
恒星と活動~彩層・コロナ~
34
Classical transition region DEM analysis
恒星と活動~彩層・コロナ~
35
dhdTTFc 2
5
~ κ
network
cell center
恒星と活動~彩層・コロナ~
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コロナの構造の多様性
恒星と活動~彩層・コロナ~
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252
27
00
22
25
025
00
2
81.18
321
2
227~ ) ( 0~ ,0~
)(27)(
2~
2
,2
~
)( 10~
)( .~ ,
27
−
−
−−
⎟⎠⎞
⎜⎝⎛→
−−−⎟⎠⎞
⎜⎝⎛
⎟⎠⎞
⎜⎝⎛
=−⎟⎠⎞
⎜⎝⎛
⋅−=
mc
mmc
ccc
ec
TkpHisolatedthermallyFT
TTHTTkpF
dsdTTFdTTHdT
kpdFF
Raymond
cmergconstHHTndsdF
χ
κχκ
κκχκ
χ
χ
sコロナループの尺度則
恒星と活動~彩層・コロナ~
38
∫∫
∫
−
=⎟⎠⎞
⎜⎝⎛=≡
⎟⎠⎞
⎜⎝⎛Γ⎟
⎠⎞
⎜⎝⎛Γ=
−
≡⎟⎟⎠
⎞⎜⎜⎝
⎛
≡−
⎟⎟⎠
⎞⎜⎜⎝
⎛=
−1
025
21
212
1
202/
0
1
025
221
02
3
2
25
3
21
02
1
,2
2
1017
56
52
1
,2
~
12
dt
t
tpTk
Hdsf
dt
t
tplk
T
TTt
tt
Tp
kdsdt
m
l
tot
m
mm
δδχκ
πγκχγ
κχ
Rosner, Tucker, & Viana (1978)
Kano & Tsuneta (1995)
恒星と活動~彩層・コロナ~
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nT=1015cm-3K
empirical
恒星と活動~彩層・コロナ~
40
L=1010 cm
恒星と活動~彩層・コロナ~
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Empirical model
RTV loop model
恒星と活動~彩層・コロナ~
恒星活動
自転速度
恒星と活動~彩層・コロナ~
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Chromospheric Activity measured by MgII h+k lines
恒星と活動~彩層・コロナ~
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Correlation:
Chromosphere
vs
corona
Ayres et al., 1981, ApJ, 247, 545.
恒星と活動~彩層・コロナ~
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Lx vs vsin I
Pallavicini et al. 1981, ApJ, 248, 279.
Rotation Activity Connection
恒星と活動~彩層・コロナ~
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R’HK vs Ro
Noyes et al. 1984, ApJ, 279, 763.
Ro ~ Ωτc
Ro Rosby number
恒星と活動~彩層・コロナ~S-index, RHK, R’HK
• Vaughan, Preston, Wilson (1978)– S ~H/(HV+HR) + K/(KV+KR)
• Middelkoop (1982) : color correction– RHK ~FHK/(σT4eff)
• Noyes et al. (1984): photospheric contr.– R’HK = RHK-Rphoto
恒星と活動~彩層・コロナ~
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恒星と活動~彩層・コロナ~
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Hartman, L. W. , Noyes, R. W.: Ann. Rev. Astron. Astrophys., 25, 271 (1987)
Skumanich(1972)’ s law ∝ t-1/2Rotation period with Time
恒星と活動~彩層・コロナ~
恒星活動
黒点・磁場
恒星と活動~彩層・コロナ~Starspot –obs tech-
• Light-curve inversion– Ii = fi Is + (1- fi)Ip fi: filling factor 0≦fi≦1
• Doppler imaging (Goncharskii et al. 77…)
恒星と活動~彩層・コロナ~
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Spot temperature contrast with respect to the photospherictemperature in active giants (squares) and dwarfs (circles). Thin lines connect symbols referring to the same star. The thick solid line is a second order polynomial fit to the data excluding EK Dra. Dots in circles indicate solar umbra (T = 1700 K) and penumbra (T = 750 K) .
Berdyugina, 2005, Living Rev. Solar Phys., 2, 8.
恒星と活動~彩層・コロナ~Stellar Magnetic Fields –obs tech-
Robinson Jr., R. R. (1980)
Zeeman triplet: Δλ(Å) ∝ 4.7×10-13gλ2B (G)
(g:ランデのg因子)
Fλ = (1-f) Fλ (B=0) + f Fλ(B≠0)
恒星と活動~彩層・コロナ~
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Magnetic field measurements for active dwarfs (circles) and giants (squares) versus the photosphere temperature. Big circles indicate the sunspot umbra (B = 3 kG) and penumbra (B = 1.5 kG). The thick solid line is a linear fit to the data, excluding the sunspot umbra.
Magnetic field measurements for active dwarfs (circles) and giants (squares) versus the filling factor. Big circles indicate the sunspot umbra (B = 3 kG) and penumbra (B = 1.5 kG). The thick solid line is a linear fit to the data, excluding the sunspot umbra
Stellar Magnetic Field Measurements(Berdyugina, 2005, Living Rev. Solar Phys., 2, 8.)
恒星と活動~彩層・コロナ~
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Filling factors of spots (open symbols) and magnetic fields (filled symbols) on the surfaces of active dwarfs (circles) and giants (squares) versus the photosphere temperature. The thick solid line is a polynomial fit to the spot filling factors. The dashed line is a fit to the magnetic field filling factor, excluding the Sun. A big circle emphasises the sunspot umbra (f ~1%).
(Berdyugina, 2005, Living Rev. Solar Phys., 2, 8.)
Filling Factors
恒星と活動~彩層・コロナ~
恒星活動
周期活動
恒星と活動~彩層・コロナ~
57
Chromospheric Ca II emission cycles for Sun-like stars, illustrating the regular cyclicvariation that is common in such stars. The Ca II emission is plotted in Mount Wilson “S-Index” units. From Radick (2000).
恒星と活動~彩層・コロナ~~100 Stars in spectral types of G0 - K5 V
• Young rapidly rotating stars– high average levels of activity– non-smooth cyclic variation.
• Stars of intermediate age (approximately 1 – 2 Gyr for 1M)– moderate levels of activity– occasional smooth cycles.
• Stars as old as the Sun and older – slower rotation rates– lower activity levels and smooth cycles.
• Stars of no variations– in the stage similar to the Maunder minimum– subgiants evolved off the main-sequence (Wright, 2004).
• vs. H/K chromospheric variation– young stars: anticorrelates with their variation in chromospheric
emission → activity cycles on young stars should be more prominent in spot patterns rather than in chromospheric plages.
58
恒星と活動~彩層・コロナ~
59
Spot cycles in the solar irradiance and V magnitudes of the RS CVn binary σ Gem and two young solar analogues AB Dor and LQ Hya. Note that the maximum of the spot area corresponds to the maximum irradiance on the Sun and minimum brightness on the stars.
恒星と活動~彩層・コロナ~
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• Sun: maximum spot area at the maximum irradiance
• Active stars: maximum spot area at minimum brightness → periodic changes of spot rotation periods in phase with the spot cycle
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