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Outline
A mid-IR coronagraph instrument with both imaging and low-resolution spectroscopic capability at 3.5-27microns
Scientific Objectives - Targets& Required SpecificationsConcept Study, Current StatusResource RequirementsDevelopment and Test PlanObserving Program
Scientific Targets
Direct Detection and Characterization of Jovian Exoplanets by
- Coronagraphic imaging
- Coronagraphic spectroscopy
- Monitoring of planetary transit
Consistency with MRD
Description in MDR Objective #1: Direct Detection and Characterization of
Exoplanets
To understand the diversity of the exo-planetary systems, we will attempt direct detection and characterization of exoplanets in the infrared wavelengths. Complement al two methods, coronagraphic observation and planetary transit monitoring, are described as key observations.
Therefore very consistent
Specification of Instrument
Parameter Specification Core wavelength (λ) 3.5−27 micron Observation mode w/wo Coronagraph, Imaging/ SpectroscopyCoronagraphic mode binary shaped pupil maskInner 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 arrayField of View ~1’ x 1’Spectral resolution ~20 and ~200Filter Band pass filters Disperser for spectroscopy transmissive devices (e.g. grism) in filter wheleActive optics cryogenic DM and TTM
Optics & Optical Elements (2)
Coronagraph mask (Binary shaped pupil mask) Laboratory demonstrated with visible light
Pupil mask PSF
Pupil shape design
PSF (simulation)
Coronagrahic direction
Non-coronagrahic direction
Discoveryangle
Dark region
Optics & Optical Elements (3)
Active optics - Deformable mirror
- Tip-tilt mirrorOther devices - Mirrors (Collimetion/Focusing)
- Beamsplitter (Short/Long channel)
- Disperser (Grism, Prism, etc.)
- Science filters
Detectors
Commercailly available detectors will be used.
Detector format num. usageInSb 1k x 1k (2k x 2k is OK) 1 science short channel
InSb 1k x 1k (2k x 2k is OK) 1 tip-tilt sensor
Si:As 1k x 1k (2k x 2k is OK) 1 science long channel
Thermal Design
Cooled by only 4.5K stageHeat load: to be updated - 16.36mW @the last report
- Design to reduce heat load is ongoing.
- Film Print Cable for DM control (parastic heat)
- New tip-tilt mirror design (heat generation)
Expected Performance
Parameter Specification Core wavelength (λ) 3.5−27 micron Observation mode w/wo Coronagraph, Imaging/ SpectroscopyCoronagraphic mode binary shaped pupil maskInner 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 arrayField of View ~1’ x 1’Spectral resolution ~20 and ~200Filter Band pass filters Disperser for spectroscopy transmissive devices (e.g. grism) in filter wheleActive optics cryogenic DM and TTM
Thermal & Cryogenic Requirement
Cooled by only 4.5K stageHeat load: to be updated - 16.36mW @the last report
- Design to reduce heat load is ongoing.
- Film Print Cable for DM control (parastic heat)
- New tip-tilt mirror design (heat generation)
Pointing / Attitude control Requirement
Requirements PerformancePointing control accuracy
0.03 [arcsec](3σ)
Pointing stability 0.03 [arcsec](0-P)/20min
Both pointing accuracy and stability are determinedBy 1/10 x λ/D @ 5umTo be realized with a internal tip-tilt mirror
Warm Electronics
Function component - Array driver
- Deformable mirror driver
- Tip-tilt mirror driver
- Mask changer
Weight: 25kg including 20% marginVolume: 400 x 500 x 200 [mm^3]
Operation & Observing Mode
Coronagrahic - Imaging
- SpectroscopyNon-coronagraphic (including monitor obs.) - Imaging
- Spectroscopy
Key Technical Issues & TRL
Cryogenic tip-tilt mirror - Design and test are ongoing.Cryogenic deformable mirror - Demonstrated with a proto-deviceCoronagraphic optics - Demonstrated with visible light
Development Plan
Cryogenic tip-tilt mirror - Design and test are ongoing.
Cryogenic deformable mirror - Demonstrated with a proto-device (32ch@95K)
- Demo. of 1K ch. device @5K is in preparation.
- Development of film print cable in ongoing (to
reduce parasitic heat)
Coronagraphic optics - High contrast demonstrated with visible light
- MIR demonstration in a cryo-chamber is in preparation.
Observation Plan to perform Science Targets
Coronagraphic imaging - the direct detection
- Coronagraphic spectroscopyNon-coronagrapic monitor - Planetary transit
Organization & Structure for Development
Scientists and engineers in JAXA, community of astronomy.
Finding and Involving engineers in companies. K. Enya, T. Kotan, T. Nakagawa, H. Kataza, T. Wada(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) T. Yamamuro (Optcraft), P. Bierden (BMC), SPICA coroangarph team
To be updated
Summary
We are developing SPICA Coronagraph Instrument (SCI)
Main targets of SCI is detection and characterization of exo-planets. It’s consistent with MDR.
Current design of SCI is presented. R&Ds of key technology is successfully done or
ongoing including cryo-TTM and DM. SCI team is consisting of many scientists and
engineers in JAXA, community of astronomy, companies.
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