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

semimajor axis [AU]

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for Earth-sized Planets

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Wavelength (μm)

Space "

O2 O2 O2 (1.27μm)

Ground "

Reflec%on  Spectra  of  Earthshine  Courtesy  of  E.  Palle  

How to characterize second Earths ?

~ 7 pc

Angular Separation

Planet - Star Contrast

Kawahara+2012, ApJ!

Crossfield 13

O2 1.27Μm!5hrsS!N"1010"S!N"55"S!N"33"S!N"1

!5Σ $5Σ

Planet DetectionJ band!1 hourMKGF

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5 10 50 100 500 100010%11

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Planet%StarContrast

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!5Σ $5Σ

Planet DetectionJ band!1 hour

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C

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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)

Cross-correlation analysis of spectra and molecular line template 1. high dispersion observation (R~105) @NIR!2. a lot of molecular lines (N > 50)

Brogi+2012, Nature

planet molecules (band) instruments refs

tau Boo b CO (K) CRIRES/VLT Brogi+12,Rodler+12

H NIRSPEC/KecK Lockwood+14

HD 189733 b CO (K) CRIRES/VLT Rodler+13,de Kok+13

H CRIRES/VLT Birkby+13

51 Peg b CO (K) CRIRES/VLT de Kok+13

HD 179949b CO,H(K) CRIRES/VLT Brogi+ in prep

wavelength [micron]

Line Intensity [cm/mol]

Methane

Acetylene

Water

Atmospheric Transmittance

Line Intensity

Carbon Monooxide

High Contrast + High Dispersion :　 直接撮像された場所を高分散分光

using CRIRES/VLTSnellen+2014, Nature

Doppler Imaging of Brown Dwarf

using CRIRES/VLT

Crossfield+2013, Nature

これを直接撮像した系外惑星でやることを狙っている！

+pi/2�-pi/2�

Extreme Adaptive Optics�

Visible Nuller�

A planet is unresolved but stellar photons are reduced�

Integrated images �

Instant images for 0.5 msec�

Kawahara+2014, accepted in ApJS, arXiv:1404.5712

High Contrast + High Dispersion : 分光コロナグラフ

瞬間的な焦点面イメージ

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

積算焦点面イメージ

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