直接撮像装置で探る系外惑星サイエンス： SEICAからSEITへ

直接撮像装置で探る系外惑星サイエンス：
SEICAからSEITへ
東京大学・地球惑星科学専攻
河原創 TMT地球型惑星探査のパイロット計画としての
SEICA on 岡山3.8m
uid
M-type
at bl
er e
m Zo
ain n
ta e!
ina
ble
)
bi
w ta
Ha
G-type
Space mission
Ground telescope
known !
exoplants
(liq
stellar mass [Msol]
C
for Earth-sized Planets
z
K-type
semimajor axis [AU]
How to characterize second Earths ?
Ground "
Space "
1.0
O2 O2
O2 (1.27μm)
0.8
Reﬂec%on Spectra of Earthshine Courtesy of E. Palle 0.6
0.4
0.2
0.5
1.0
1.5
Wavelength (μm) 2.0
2
2.0
distance $pc%
3.0
5.0
Planet - Star Contrast
O2 1.27Μm!5hrs
%7
10
10 -7
S!N"10
Planet%Star Contrast
5Σ
C
7.0
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%8
10
10-8
10.0
15.0
Planet Detection
J band!1 hour
10"S!N"5
M
5"S!N"3
K
3"S!N"1
G
!5Σ $5Σ
F
Crossfield 13
5Σ
%9
10-9
10
5Σ
%10
10
10-10
Photon%noise limited
IFS "Kasper&10#
EPOL "Kasper&10#
~ 7 pc
%11
1010-11
5
50 0.1
100
50
10000
Angular Separation $mas%
10
10 00
0.01
500Angular
1000 Separation
✓
Kawahara+2012, ApJ!
今日の話題
岡山3.8m新望遠鏡に近赤外高分散分光装置を
Spectroscopic Direct Detection
CO & H2O were detected for hot Jupiters (
) so ) (Brogi+12, Rodler+12, Birkby+13 etc)
~50 CO lines v=110 ± 3 km/s!
(VLT/CRIRES: R~87,000)
planet
tau Boo b
molecules
instruments
(band)
CRIRES/VLT
Brogi+12,Rodler
+12
NIRSPEC/
KecK
Lockwood+14
CO (K)
CRIRES/VLT
Rodler+13,de
Kok+13
H
CRIRES/VLT
Birkby+13
CO (K)
CRIRES/VLT
de Kok+13
CO,H
(K)
CRIRES/VLT
Brogi+ in prep
CO (K)
H
HD 189733 b
51 Peg b
HD 179949b
refs
Brogi+2012, Nature
Cross-correlation analysis of spectra and molecular line template
1. high dispersion observation (R~105) @NIR!
2. a lot of molecular lines (N > 50)
Atmospheric
Transmittance
Line Intensity [cm/mol]
Carbon Monooxide
Water
Line Intensity
Methane
Acetylene
wavelength [micron]
High Contrast + High Dispersion : 直接撮像された場所を高分散分光
Snellen+2014, Nature
using CRIRES/VLT
Doppler Imaging of Brown Dwarf
Crossfield+2013, Nature
using CRIRES/VLT
これを直接撮像した系外惑星でやることを狙っている！
High Contrast + High Dispersion : 分光コロナグラフ
Kawahara+2014, accepted in ApJS, arXiv:1404.5712
瞬間的な焦点面イメージ
Extreme Adaptive Optics
Visible Nuller
積算焦点面イメージ
-pi/2
+pi/2
Instant images for 0.5 msec
空間的には分解できない惑星でも、恒星の光子ノイズを抑制できる
A planet is unresolved but stellar photons are reduced
1. 系外惑星キャラクタリゼーションにおいて
高コントラスト＋高分散のできる装置の重要性
!
2. 岡山3.8m新望遠鏡に近赤外高分散分光装置
を置くメリットをさらに議論したい
(フレア星＠晩期型や銀河、円盤では？)
!
高分散におけるExAOの装置的重要性→小谷講演

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