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									        SPICA infrared coronagraph
     and the study of exo-planets with it
                               Barcelona, Spain,
                             September 17th, 2009

           K. Enya, T. Nakagawa, H. Kataza, T. Kotani (ISAS/JAXA),
K. Haze (SOUKENDAI, ISAS/JAXA), S. Higuchi (Univ. of Tokyo, ISAS/JAXA),
  T. Miyata, S. Sako, T. Nakamura (IoA/Univ. Tokyo), M. Tamura, J. Nishikawa,
T. Yamashita,N. Narita, H. Hayano (NAOJ), Y. Itoh (Kobe Univ.), T. Matsuo(JPL),
      M. Fukagawa, H. Shibai (Osaka Univ.), M. Honda (Kanagawa Univ.),
                    N. Baba, N. Murakami(Hokkaido Univ.),
  L. Abe (Nice Univ), O. Guyon (NAOJ/SUBARU), M. Venet (Marseille Univ.),
      T. Yamamuro (Optcraft), P. Bierden (BMC), SPICA coroangarph team


                                               Contact: Keigo ENYA (enya@ir.isas.jaxa.jp)
           SPICA mission
                       • Please see presentation by
                         Nakagawa.
                       •An infrared space observatory
                         - Aperture: 3.5m
                         - Main wavelength: 5-200micron
                         - Telescope temperature: 5K
                         - Cooling: Mechanical cryo-coolers
                           and radiation
                         - Orbit: Sun-Eatrh L2 Halo
                         - Launch year: 2018
                       • International mission including
                         JAXA/ESA collaboration.
                       • Pre-porject phase is ongoing.

We consider SPICA is a unique opportunity for
coronagraphic observation for exo-planet study.
What can we do with coronagraph for SPICA?
- Spectroscopy of atmosphere for outer exo-planets
   Detection                                             From
    - More than 300 exo-planets by e.g., RV method
    - Direct imaging achieved!, while number of
     object is still small                               (Marois et al. 2008)   Kalas et al. (2008)

   Spectroscopy of atmosphere by transit method
    - H2O, CH4, CO2 are found (Swain et al, Tinetti et al).
    - Hot topic, while the object is biased on hot-Jupiters.
   Next step
    - systematic characterization of the atmosphere
                                                          To
      of many outer Jovian exo-planets to
      understand whole planetary system.
    - We are developing SPICA coronagraph
      instrument (SCI) having spectroscopy mode.
                                                   An expected spectrum by SCI. (spectrum
                                                     Is from Burows et al. 2Mj mass, 100Gyer old
                                                     aroudn G2V star ) figure is by Kotani.
Specification of SCI                                                                              (1)

Parameter                 Specification
Core wavelength (λ)        3.5−27 micron
Observation mode           w/wo Coronagraph, Imaging/
              •Aaa
Coronagraphic mode
                           Spectroscopy
                           binary shaped pupil mask
              •Aaa
Inner working angle (IWA) ~3.3×λ/D *
Outer working angle (OWA) 16×λ/D
Throughput                ~20%
Contrast                   10-6 @PSF ( ~10-7 after subtraction)
Detector                    1k×1k Si:As, InSb array
                                                                        Estimation is T Matsuo based on
Field of View              ~1’ x 1’
                                                                         Sivaramakrishnan et al.2009,
Spectral resolution         ~20 and ~200
                                                                                Krist et al. 2007
Filter                      Band pass filters
Disperser for spectroscopy transmissive devices (e.g. grism)
                             in filter whele
Active optics               cryogenic DM and TTM                  (2)

           • Comparison to JWST coronagraph
                (1) Higher contrast (10-6 in a PSF. )
    (2) Spectroscopy mode with continuous wavelength coverage
 Coronagraph method selection
                   • Background
          - Broad band spectroscopy is needed
      - Telescope pointing is influenced by vibration
     made by mechanical cryo-coolers, compressors,…
 • We focused on binary shaped pupil mask
- Achromatic work (except PSF size scaling with wavelength)
      - Very robust against telescope pointing error

                    Pupil
                    shape                  e.g.,
                                           Jaquinot & Roizen dozierr(1964),
                                           Spergel (2001),
                                           Vanderbei et al. (2004)
                                           Kasdin et al (2005),
                     PSF
    Binary mask for SPICA pupil
                                              Green et al.(2006) : 6 diffraction tail
• Obstruction by the secondary mirror
  and support sturcture is serious problem.
    Binary mask for SPICA pupil
                                                Green et al.(2006) : 6 diffraction tail
• Obstruction by the secondary mirror
  and support sturcture is serious problem.
• Solution by 1-D coronagraph by multipled
   barcode mask
   Pupil shape design            PSF (simulation)             - IWA=3.3 lambda/D,
                                           Non-corona
                                                              - Contrast ~6
                                           grahic direction
                                                              - Large discovery angle
                                                               (only 2 diffraction tail)

                               Discovery                    The principle of a barcode
                               angle                        mask itself is presented
                                               Coronagrahic by Kasdin et al(2005).
                                               direction
                                                            LOQO is used presented
                                                            by Vanderbei(1995)
            Mask rotation

Imaging 1




Then…
            Mask rotation

Imaging 1



                            Total discovery angle is
                            enlarged more w/o
                            telescope roll

Imaging 2
                            (Practically mask
                            rotation will be
                            realized by mask
                            changer mechanism)
                    Labo. experiment




   Demo. of principle with masks on substrate               Enyta et al (2008)
     - with precise mask manufactured on BK7 substrate
       by electron beam drawing, visible laser, w/o AO
        → contrast of 6x10-8 achieved
   - Demo. of free standing (no substrate) mask for MIR
     coroangraph
     - experiment with visible laser, w/o AO was performed
        → 7x10-7 was confirmed.
     - demonstration in MIR is in preperation.
Design of SCI
Cryogenic active optics

   Cryogenic deformable mirror(DM)
    - MEMS DM: compact, large format (many
      channels)
    - Demo. with a prototype device succeeded.
    - Toughness demonstration against launch
      vibration is ongoing (numerical structure
      analysis, experimental vibration test) in the
      colaboration with BMC.
   Development of a cryogenic tip-tilt
    mirror is also ongoing.
    - to cancel the telescope pointing error produced
                                                        Enya, Kataza, Bierden. (2008)
      by mechanical vibration
    SCI for monitor observation of planetary transit
•   Monitor observation of planetary transit
    - Powerful method to obtain atmospheric feature of exo-planets.
    - We are seriously considering to perform planetary transit observation
• Why will we use SCI for the transit observation?
    - SCI has “non coronagraph mode” thanks to the mask changing
      machanism.
    - Simultaneous 1-27micron coverage of spectroscopy by two detector
      (a Si:As and a InSb. Wavelength region < 3.5um is not coronagraphic, but still
      have sensitivity)
    - The best pointing accuracy in the SPICA FPI(0.”03) thanks to TT.
    - Deforcusing by a deformable mirror: a potential solution for
      saturation problem
    - Internal calibrator designed for transit obsrevation.
    - Quick readout
• Other MIR instruments of SPICA are also potentially useful.
    - MIRACLE: fide field camera (6’x 6’ fov)
    - MIRHES: high dispersion spectrometer (R=30000)
Related presentation
 • Nakagawa et al. SPICA mission (talk)
 • Kotani et al. Our first result of WFC experiment (poster)
     - Contast has improved from 10-4 to better than 10-6 successfully.
 • Haze et al. Experiment with a vacuum chamber (poster)
                 SPICA as a part of the pathway
                      to Habitable planets
   Giant missions targeting habitable planets in future
    - Essentially important, no doubt
    - should be realized, probably in giant international collaboration
      (Both TPF-C and TPF-I may be OK as TPF with China and TPF with India)
                  SPICA as a part of the pathway
                       to Habitable planets
   Giant missions targeting habitable planets in future
    - Essentially important, no doubt
    - should be realized, probably in giant international collaboration
      (Both TPF-C and TPF-I may be OK as TPF with China and TPF with India)


   SPICA as a part of the pathway
    - Realistic goal : Jovian planets with 10-6 contrast
    - Scientific product : atlas of varisou exo-Jovian planet spectrum.
    - Technical product : light weight 3.5m telescope of SiC, high
      contrast optics, the first space telescope with fine WFC (except
      military satelite???), extensive study for stability,…
    - JAXA/ESA mission pre-project ongoing for near future!

   Both are important !!! Hopefully complementary.
                       Summary
 We are developing a MIR coronagraph instrument
  (SCI) as one of FPI for SPICA.
 The primary target of SCI is the direct detection of
  exo-Jovian planets and spectroscopy of their
  atmospheric feature, including importantline,
  e.g., H2O, CH4, CO2, NH3.
 Unique capability of SCI.
    - High contrast (10-6 in a PSF)
    - Spectroscopy mode with continuous wavelength
      coverage (3.5-27 micron)
 Technical demonstrations are performed, or
  successfully ongoing.
 Planetary transit is quite important by-product.
                      Summary
 We are developing a MIR coronagraph instrument
  (SCI) as one of FPI for SPICA.
 The primary target of SCI is the direct detection of
  exo-Jovian planets and spectroscopy of their
    We are deeply grateful to all of organizers
  atmospheric feature, including importantline,
    of H2O, CH4, CO2, NH3.
  e.g., the conference, contributers for our
    project, pioneers of this so interesting field,
 Unique capability of SCI.
    and everyone related to this work.
    - High contrast (10-6 in a PSF)
    - Spectroscopy mode with continuous wavelength
      coverage (3.5-27 micron)
 Technical demonstrations are performed, or
  successfully ongoing.
 Planetary transit is quite important by-product.

								
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