Wideband Infrared Spectrometer for Characterization of Transiting Exoplanets with Space Telescopes

TL;DR

This paper proposes a simple, stable, wideband infrared spectrometer design for space telescopes to characterize transiting exoplanets, covering 1-13 microns with high throughput and spectral resolution.

Contribution

It introduces a novel, compact, and stable spectrometer design with wide wavelength coverage and high throughput, suitable for space-based exoplanet characterization.

Findings

Design achieves 1-13 micron coverage with R~200-300.

No moving parts in the spectrometer enhance stability.

Evaluates defocusing effects on spectral resolution.

Abstract

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.