A high dynamic-range instrument for SPICA for coronagraphic observation of exoplanets and monitoring of transiting exoplanets

Enya, Keigo; Abe, Lyu; Takeuchi, Shinsuke; Kotani, Takayuki; Yamamuro, Tomoyasu

doi:10.1117/12.893508

Cited by 9 publications

(9 citation statements)

References 45 publications

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“…We have been developing a wideband, simple, compact spectrometer which has no moving mechanical parts, for which the primary scientific objective is the characterization of exoplanets [e.g., Enya & Fujishiro (2014); Enya et al (2011)]. In this paper, a wideband spectral disperser manufactured using ZnS is presented.…”

Section: Science Objectivementioning

confidence: 99%

WIDEBAND SPECTRAL DISPERSER MADE OF ZnS FOR EXOPLANET CHARACTERIZATION USING SPACE-BORNE TELESCOPES

Enya¹,

Fujishiro²

2017

Publications of The Korean Astronomical Society

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We present the development of a spectral dispersion device for wideband spectroscopy for which the primary scientific objective is the characterization of transiting exoplanets. The principle of the disperser is simple: a grating is fabricated on the surface of a prism. The direction of the spectral dispersion power of the prism is crossed with the grating. Thus, the prism separates the spectrum into individual orders while the grating produces a spectrum for each order. In this work, ZnS was selected as the material for the cross disperser, which was designed to cover the wavelength region, λ = 0.6-13 µm, with a spectral resolving power, R ≥ 50. A disperser was fabricated, and an evaluation of its surface was conducted. Two spectrometer designs, one adopting ZnS (λ = 0.6-13 µm, R ≥ 300) and the other adopting CdZnTe (λ = 1-23 µm, R ≥ 250), are presented. The spectrometers, each of which has no moving mechanical parts, consist simply of a disperser, a focusing mirror, and a detector.

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Section: Science Objectivementioning

confidence: 99%

WIDEBAND SPECTRAL DISPERSER MADE OF ZnS FOR EXOPLANET CHARACTERIZATION USING SPACE-BORNE TELESCOPES

Enya¹,

Fujishiro²

2017

Publications of The Korean Astronomical Society

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“…Furthermore, cross dispersion is adopted for the spectroscopy in each channel (Enya et al 2011). A small number of optical devices in each channel makes the design simple and compact and promotes throughput.…”

Section: Baseline Designmentioning

confidence: 99%

“…There are many absorption features of exoplanet atmospheres in the infrared wavelength region, e.g., H 2 O (1.13, 1.38, 1.9, 2.69, 6.2micron), CO 2 (1.21, 1.57, 1.6, 2.03, 4.25micron), O 3 (4.7, 9.1, 9.6micron), O 2 (1.27micron), CH 4 (1.65, 2.2, 2.31, 2.37, 3.3, 6.5, 7.7micron), NH 3 (1.5, 2, 2.25, 2.9, 3.0, 6.1, 10.5micron), and so on (e.g., Tinetti et al 2012, and their references).…”

Section: Introductionmentioning

confidence: 99%

Wideband infrared spectrometer for characterization of transiting exoplanets with space telescopes

Enya

2012

Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave

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This paper presents a conceptual design for a spectrometer designed specifically for characterizing transiting exoplanets with space-borne infrared telescopes. The design adopting cross-dispersion is intended to be simple, compact, highly stable, and has capability of simultaneous coverage over a wide wavelength region with high throughput. Typical wavelength coverage and spectral resolving power is 1-13 micron with a spectral resolving power of ~ a few hundred, respectively. The baseline design consists of two detectors, two prisms with a dichroic coating and microstructured grating surfaces, and three mirrors. Moving parts are not adopted. The effect of defocusing is evaluated for the case of a simple shift of the detector, and anisotropic defocusing to maintain the spectral resolving power. Variations in the design and its application to planned missions are also discussed.

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“…Among the instruments, the SPICA Coronagraph Instrument (SCI; Enya et al 2011) has the most stringent requirements on a wave front error (WFE) and thus requires highly accurate optics at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Experiments of Off-Axis Mirror Optics of Aluminum for Space Infrared Missions

Oseki¹,

Oyabu²,

Ishihara³

et al. 2017

Publications of The Korean Astronomical Society

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We report our research on aluminum mirror optics for future infrared astronomical satellites. For space infrared missions, cooling the whole instrument is crucial to suppress the infrared background and detector noise. In this aspect, aluminum is appropriate for cryogenic optics, because the same material can be used for the whole structure of the instrument including optical components thanks to its excellent machinability, which helps to mitigate optical misalignment at low temperatures. We have fabricated aluminum mirrors with ultra-precision machining and measured the wave front errors (WFEs) of the mirrors with a Fizeau interferometer. Based on the power spectral densities of the WFEs, we confirmed that the surface accuracy of all the mirrors satisfied the requirements for the SPICA Coronagraph Instrument. We then integrated the mirrors into an optical system, and examined the image quality of the system with an optical laser. As a result, the total WFE is estimated to be 33 nm (rms) from the Strehl ratio. This is consistent with the WFEs estimated from the measurement of the individual mirrors.

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A high dynamic-range instrument for SPICA for coronagraphic observation of exoplanets and monitoring of transiting exoplanets

Cited by 9 publications

References 45 publications

WIDEBAND SPECTRAL DISPERSER MADE OF ZnS FOR EXOPLANET CHARACTERIZATION USING SPACE-BORNE TELESCOPES

WIDEBAND SPECTRAL DISPERSER MADE OF ZnS FOR EXOPLANET CHARACTERIZATION USING SPACE-BORNE TELESCOPES

Wideband infrared spectrometer for characterization of transiting exoplanets with space telescopes

Laboratory Experiments of Off-Axis Mirror Optics of Aluminum for Space Infrared Missions

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