Second-­‐Earth	  Imager	  for	  TMT	  (SEIT)	
Taro	  Matsuo （NAOJ）	  Takayuki	  Kotani	  （JAXA/ISAS）	  Naoshi	  Murakami（Hokkaido	  Univ.）	  Motohide	  Tamura	  （NAOJ）	  1	

Background	• More	  than	  500	  planets	  have	  been	  discovered	  by	  several	  indirect	  techniques.	  
• First	  success	  of	  direct	  imaging	  of	  gas	  giants	  In	  2008.	  	  Imaging of gas giants around HR8799• Kepler	  transit	  satellite	  detects	  more	   （Marois et al. Science 2008）
than	  100	  Earth-­‐like	  planets.	  
1	  .	  Earth-­‐like	  planets	  in	  HZ	  are	  common.	  
2.	  	  Technology	  developments	  for	  direct	  imaging	  rapidly	  make	  progress.	  	   To	  directly	  detect	  Earth-­‐like	  planets,	  and	  search	  for	  life.	  	  Periods and radii of planets
2	
discovered by Kepler transit satellite 	Future	  Direct	  Imaging	  Programs	
Current	

• SPACE	HST	• Ground	
Now	

2014	

2018	

2025~	

1.	

3.	

JWST	  SPICA	  Cold	  giants	  around	  old	  	  nearby	  stars	

TPF	  Search	  for	  biological	  ac^vity	

2018	

2.	
+	  ExAO	
(in	  near	  future)	
8m-­‐telescopes	  (Subaru/HiCIAO,	  Gemini/GPI	  etc)	  Self-­‐luminous	  giants	  around	  young	  stars	  TMT	  E-­‐ELT	  Extreme	  Large	  Telescopes	
3	What	  can	  we	  do	  with	  ELTs?	

Exoplanet	  Imagers	  for	  ELTs	
• Several	  instruments	  for	  exoplanet	  studies	  already	  proposed.	  
-­‐	  E-­‐ELT:	  	  	  	  	  VLT/SPHERE	   Exo-­‐Planet	  Imaging	  Camera	  and	  Spectrograph	  (EPICS)、	  	  	  	  VLT/ZIMPOL	  	   Exoplanet	  Polarimeter	  for	  EPICS	  (EPOL)	  -­‐	  TMT:	  	  	  	  	  Gemini/GPI	  Planet	  Forma^on	  Imager	  (PFI)	  Contrast	

1E-7	
Earth-like
1E-8	 planets	

Jupiter-likeplanets	

1E-9	

1E-10	
0.01	
0.10	
Angular separation (arcsec)	
Detection limit of EPICS	

Detection limit of PFI	Second-­‐Earth	  Imager	  for	  TMT	  (SEIT)	
• Current	  status： Extreme	  AO	  projects	  for	  8m-­‐class	  telescopes	  directly	  applied	  to	  ELTs	  	  Reﬂected	  light	  of	  Jupiter-­‐like	  planets	  A breakthrough needed for direct imaging
of *Earth*-like planets with ELTs!

• Our	  proposal:	  	  	  	  The	  ﬁrst	  imaging	  of	  Earth-­‐like	  planets	  with	  TMT,	  using	  a	  novel	  technique	  for	  high	  contrast	  imaging.	  

 Second-Earth Imager for TMT (SEIT)	

5	Science	  Requirements	  for	  SEIT	
Important parameters: “IWA” and “contrast”	
1.E-06	

• あ	SEIT	

PFI	

10-­‐8	  at	  0”.01	  10-­‐8	  at	  0”.01	  10-­‐9	  at	  0”.1	

Inner	  working	   0”.01	  	  0”.03	  Angle	  (IWA)	 (1.5l/D	  at	  1.0µm)	 	  (3l/D	  at1.6µm)	  	Contrast	

Science Requirements	
Contrast	

Subaru/HiCIAO	

Condition for Earth-like (solid)
and1.E-07	
Super-Earth planets (dotted)
1.E-08	SEIT	TMT/PFI	

1.E-09	● “Difficult” to detect Earth-like planetswith TMT/PFI and E-ELT/EPICS● Key is “IWA”.
Very small IWA relaxes the required contrast.
Planet is brighter as A.S. is smaller 	

E-ELT/EPICS	

1.E-10	
0.01	

0.1	

1	

Angular Separation (arcsec)	

Detection limits for future direct
imaging projects	
6	

Target	  priority:	  1.	  Earth-­‐like	  Planets	  in	  HZ	   K	  and	  M-­‐type	  stars	  2.	  Earth-­‐like	  Planets	  outside	  HZ	   F	  and	  G-­‐type	  stars	  Stellar	  mass	  in	  unit	  of	  mass	  of	  the	  Sun	

Targets	  for	  TMT/SEIT	Area	  where	  SEIT	  detects	  Earth-­‐like	  planets	  around	  stars	  at	  10pc	
1.0	

S.S.	

Gl 581	

0.3	

0.1	

1.0	0.1	
Semi-­‐major	  Axis	  (AU)	

10.0	

Habitable Zone (Kasting+1993) andTMT/SEIT 	
7	

Number	  of	  Targets	  	Sta^s^cal	  study	  on	  habitable	  planets	

：Contrast	  Limits	  for	  super-­‐	  Earths	

↑	IWA	↑	HZ	  radius	↑	• Much	  more	  late-­‐type	  stars	  (K	  and	  M	  stars)	  compared	  with	  early-­‐type	  stars	  in	  20pc.	  
• #	  of	  targets	  for	  Earth-­‐like	  planets	  in	  HZ： ~	  80	  • #	  of	  targets	  for	  super-­‐
Earth	  like	  planets： ~	  200	  ：Contrast	  Limits	  for	  “1”	  Earth-­‐mass	  planets.	

Sensi^vity	  limits	  for	  super-­‐Earths	  	Distance	
HZ	  radii	  of	  nearby	  K	  and	  M-­‐type	  stars	

8	Japanese	  Roadmap	  for	  Exoplanets	
Ground-­‐based	  telescopes	  1999	  Subaru	  8.2m	  Indirect	  detec^on	  of	  Exoplanets	  on	  going	  -­‐Doppler	  	  -­‐Transit	  2009	  2014	  HiCIAO+AO188	  IR	  Doppler	  -­‐	  SEEDS	  project	  star^ng.	  	  -­‐	  Indirect	  detec^on	  of	  -­‐	  Several	  important	  low-­‐mass	  planets	  around	  papers	  published!	  
M	  stars	  	  -­‐	  Direct	  imaging	  of	  a	  planet	  candidate	  around	  -­‐	  IRD	  already	  funded	  and	  observa^on	  star^ng	  in	  GJ	  758.	  
2014.	  
-­‐	  Fine	  structures	  in	  planet	  forming	  region	  around	  AB	  Aurigae	  2018	  TMT/SEIT、PFI	  -­‐	  Direct	  Imaging	  of	  ExoEarth	  around	  late	  types	  stars	  with	  SEIT?	  

9	Synergy	  of	  Subaru/IRD	  and	  TMT/SEIT	• Characteriza^on	  of	  these	  Earth-­‐like	  planets	  with	  TMT/SEIT.	  

1000	  TMT/SEIT	  Gl	  581	  100	  Gl	  876	  10	  1	  0.1	  0.01		  	  *DETECTION*	  	  	  *CHARACTERIZATION*	  HZ	IRD	  (1m/s)	  Planet	  Mass	  (Me)	

• Indirectly	  detec^on	  of	  Earth-­‐like	  planets	  around	  M	  stars.	  

0.1	

1	10	

Semi-­‐major	  Axis	  (AU)	

SUBARU/IRD	  detec^on	  limit	  with	  1m/s	  accuracy	  TMT/SEIT	  detec^on	  limit	  around	  a	  star	  at	  5pc	  10	

：*Bright* interference light	

SEIT	  Concept	

：*Dark* interference light	
WF sensing and Post-processing	

W.P.	

E1+E2	

E1+E2	(reference)	

E1-E2	

From TMT	ExAO	

Nulling interferometerwith polarization(coronagraph)	

Pupil
Remapping
Imager 	

E1-E2	(science)	
Camera	Requirements: Very small IWA (10mas) and High contrast (10-8)
Keys:
Interferometric coronagraph and Interferometric post-processing
Non-common path error perfectly removed
 High sensitive WF sensing on science camera with lots of photons
A novel observing technique:	
1. To separate *Bright* and *Dark* interference lights with a nulling interferometer
2. To accurately measurement of WF error from bright interference lights
3. To reconstruct brightness on sky from dark interference lights and the calculated
11	wavefront error.	

SPLINE 〜Shearing Nulling Interferometer with Savart plates〜
Murakami & Baba Opt. L. (2010)	
Original shearing nulling interferometer (PFI)	

+π	

2nd-Order SPLINE 	
P1 (0o)SPP2 (90o)
OutputP2(90°)*Dark* interference light
P2(0°)  *Bright* interference light	

Input

x-shear(a)

(b)

y(c)

yoe 	x(a)12	  eo 	oe 	x(b)yx

Advantage of SPLINE：• Suitable for segmented mirrors like TMT• *Common* optical path  very *stable*
yoe+eo 	 • Polarization  very *wide* band• Be able to separate *Bright* and *Dark*
interference lights just before cameraxwith Wollaston Prismeo 	(c)yeo 	 oe 	xStar at central null
Planet at bright fringe	

yx

Laboratory	  demonstration	  of	  SPLINE	  	  	  N. Murakami, Y. Konno, N. Baba et al., in prep. (2011)
White-­‐light	  source	  	  	  	  X-­‐shear	  	  	  	  Y-­‐shear	  	  	  	  Savart	  plates	  	  To	  CCD	  camera	  	  Polarizers	  	  	  @Pupil	  plane	  	  Bright	  	  1	  	  	  Null	  	  N.	  Murakami,	  Y.	  Konno,	  N.	  Baba	  et	  al.,	  in	  prep.	  (2011)	  	  	  Y-­‐shear	  	  X-­‐shear	  	  10-­‐3	  	  	  @Image	  plane	  	  Bright	  	  	  	  Null	  	  	  	  Peak	  null	  ~10-­‐5	  	  (Bandwidth>30%	  @λ0=600nm)	  	  0.01	  	  	  10-­‐8	  	  :	  Ghosts	  	  Pupil Remapping Imager（Perrin et al. 2006; Kotani 2009)	

Lenslet array
Single-mode
fibersRedundant Configuration + Corrugated Wavefront

Non-Redundant Configuration+ Spatially Filtered Wavefront	 Spatial	 filter	 cleans	 wavefront	 	 	 Roll	 of	 pupil	 remapping	 imager:	 	 	 	 	 	 	 	 	 -To	 measure	 wavefront	 error	 with	 high	 accuracy	 	 	 	 	 	 	 	 	 -To	 reconstruct	 an	 original	 wavefront	 coming	 from	 source	 plane.	 	 	 Contrast	 =	 Photon	 noise	 limited	 (i.e.	 perfect	 AO)	 

	 Very	 small	 IWA	 (〜λ/D)	 and	 High	 contrast	 imaging	 	 

14	Successful demonstrations
Lab experiment

CCD Image

Kotani et al., 2009,

Theoretical Estimation

Reconstructed image

On-sky test at Lick
3m telescope

Expected performance for only pupil remapping imager	

Paris Obs., UC Berkley, JAXA/ISAS	

9-fiber system, Spectrointerferometry (600-800nm)

Interferogram of Vega

800 nm

600 nm 15	

SEIT	  Concept	
：*Bright* interference light	TO PFI	：*Dark* interference light	
W.P.	

E1+E2	
E1-E2	
From TMT	PFI AO	

Nulling interferometerwith polarization

PupilRemapping
Imager 	

E1+E2	(reference)	
E1-E2	(science)	
Camera	

TMT/SEIT (uncooled)	

Phase screen
AtmosphericPhase Screen	 correctedby PFI AO

Dark interference Bright interference
light (E1+E2)	
light (E1-E2)	

ScienceReference(To measure WF)	(To reconstructsource on sky)	

Simula^on	(Kotani, Matsuo, Murakami, in prep.)	
• Flux	  ra^o	   Star：Planet=1:10-­‐6	  • Angular	  separa^on	  of	  planet：~13mas	  Planet detection	

FOV~0”.1	

Achieved contrast
Nulling interferomter(SPLINE) ~3桁
Pupil Remapping Imager (PRI) ~3桁	Accuracy of WF measurement: ~1/200λ（Photon noise limited）

Expected contrast in 1hour： ~	 3600 × 10 6 = 1.7 × 10 8
Science requirement satisfied.
1 Earth mass planet detection with TMT!

17	

TMT/SEIT	  and	  TMT/PFI	SEIT	

PFI	Science	  Driver	Imaging	  of	  Earth-­‐like	  planets	

Imaging	  of	  reﬂected	  gas	  giants	  Imaging	  of	  ﬁne	  structure	  of	  disks	

Wavelength	Y,	  J,	  H	  (uncooled)	

J,	  H,	  K	Contrast	

10-­‐8	  at	  0”.01	  10-­‐8	  at	  0”.03	  10-­‐9	  at	  0”.1	

Inner	  working	  Angle	0”.01	  (1.5l/D	  at	  1.0µm)	 0”.03	  (3l/D	  at	  1.6µm)	  	Spectral	  resolu^on	20,	  100	50	  (full	  FOV),	  500	  (par^al	  FOV)	

Field-­‐of-­‐View	

0”.1	0”.7	

Sensi^vity	  (1hr,	  5sigma)	

28	  mag	  in	  J	  band	

28mag	  in	  H	  band	

Observing	  mode	Imaging	Spectral	  and	  Polarimetric	  Imaging	

TMT/SEIT is specialized in imaging of Earth-like planets.
TMT/PFI is a general instrument for exoplanet and disk studies.	

TMT/SEIT is complementary with TMT/PFI.
 *NOT* competitive instruments	

18	

SEIT	  project	
• SEIT:	  Science	  and	  Instrument	  teams	  *	  Science	  team	  (~10people)	  	  	  	  	  -­‐	  Subaru/IRD	  members	  	  	  	  	  	  -­‐	  Some	  theorists	  related	  to	  astrobiology	  and	  planetary	  science	  *	  Instrument	  team	  (~10people)	  	  	  	  	  -­‐	  Subaru/HiCIAO	  and	  SPICA	  members	  	  	  	  	  	  -­‐	  Some	  experts	  on	  ExAO	  and	  high	  contrast	  imaging	  	  	  	  	  	  	  	  	  	  	  	  • Cost	  es^mate	  	  	  	  	  -­‐	  ~$2	  million	  for	  only	  the	  SEIT	  produc^on	  	  	  	  	  	  -­‐	  $10	  million	  for	  ExAO	  (ref.	  	  PFI	  proposal	  document)	  	  -­‐	  Founda^on	  primarily	  from	  external	  sources	  19	

Schedule	• Search	  for	  Earth-­‐like	  planets	  from	  space	  auer	  2025	   First	  Light	  before	  2025	  -­‐ 2009	   	  	  	  TMT/SEIT	  project	  started	  -­‐ 2011	  	  	  	  	  	  	  	  Submission	  of	  TMT/SEIT	  proposal	  to	  TMT	  SAC	  -­‐ 2012-­‐2015 Detailed	  design	  -­‐ 2015-­‐2018	  	  	  Assembling	  and	  Test	  	  	  	  	  	  	  	  20	Conclusions	• Second-­‐Earth	  Imager	  for	  TMT	  (SEIT)	  is	  the	  world’s	  ﬁrst	  imaging	  of	  Earth-­‐like	  planets	  in	  HZ	  around	  late-­‐type	  stars.	  
• A	  novel	  concept	  makes	  a	  breakthrough	  for	  direct	  imaging	  science	  with	  ground-­‐based	  telescopes.	  	  • TMT/SEIT	  is	  complementary	  with	  TMT/PFI.	  PFI	  AO	  can	  be	  shared	  with	  SEIT	  and	  PFI.	  	  	  NOT	  compe^^ve	  • The	  proposal	  will	  be	  submiwed	  to	  TMT	  SAC	  in	  2011.	  	  21