Direct detection and characterization of exoplanets using imaging Fourier transform spectroscopy

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Hauptverfasser: Zhang, Jingwen, Bottom, Michael, Serabyn, Eugene
Format: Preprint
Veröffentlicht: 2023
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author Zhang, Jingwen
Bottom, Michael
Serabyn, Eugene
author_facet Zhang, Jingwen
Bottom, Michael
Serabyn, Eugene
contents Space-based direct imaging provides prospects for detection and spectral characterization of exoplanets at optical and near-infrared wavelengths. Integral field spectrographs (IFS) have been historically baselined for these mission concepts. However, multiple studies have revealed that detector noise is a serious obstacle for such instruments when observing extremely faint targets such as Earth-like planets. Imaging Fourier transform spectrographs (iFTS) are generally less sensitive to detector noise, and have several other compelling features such as simultaneous imaging and spectroscopy, smaller-format detector requirements, and variable spectral resolution. To date, they have not been studied as options for such missions. In this work, we compare the capabilities of integral field spectrographs and imaging Fourier transform spectrographs to directly obtain spectra from an Earth-like planet using analytic and numerical models. Specifically, we compare the required exposure time to achieve the same signal-to-noise ratio of the two architectures over a range of detector and optical system parameters. We find that for a 6-meter telescope, an IFS outperforms an iFTS at optical wavelengths. In the near-IR, the relative efficiency of an IFS and iFTS depends on the instrument design and detector noise. An iFTS will be more efficient than an IFS if the readout noise of near-IR detector is above 2-3 e-/pix/frame (t_frame=1000s), which correspond to half to one-third of detector noise of the state-of-art. However, if the readout noise is further reduced to below this threshold, the performance of an IFS will experience a substantial improvement and become more efficient. These results motivate consideration of an iFTS as an alternative option for future direct imaging space missions in the near-IR.
format Preprint
id arxiv_https___arxiv_org_abs_2310_15231
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Direct detection and characterization of exoplanets using imaging Fourier transform spectroscopy
Zhang, Jingwen
Bottom, Michael
Serabyn, Eugene
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Space-based direct imaging provides prospects for detection and spectral characterization of exoplanets at optical and near-infrared wavelengths. Integral field spectrographs (IFS) have been historically baselined for these mission concepts. However, multiple studies have revealed that detector noise is a serious obstacle for such instruments when observing extremely faint targets such as Earth-like planets. Imaging Fourier transform spectrographs (iFTS) are generally less sensitive to detector noise, and have several other compelling features such as simultaneous imaging and spectroscopy, smaller-format detector requirements, and variable spectral resolution. To date, they have not been studied as options for such missions. In this work, we compare the capabilities of integral field spectrographs and imaging Fourier transform spectrographs to directly obtain spectra from an Earth-like planet using analytic and numerical models. Specifically, we compare the required exposure time to achieve the same signal-to-noise ratio of the two architectures over a range of detector and optical system parameters. We find that for a 6-meter telescope, an IFS outperforms an iFTS at optical wavelengths. In the near-IR, the relative efficiency of an IFS and iFTS depends on the instrument design and detector noise. An iFTS will be more efficient than an IFS if the readout noise of near-IR detector is above 2-3 e-/pix/frame (t_frame=1000s), which correspond to half to one-third of detector noise of the state-of-art. However, if the readout noise is further reduced to below this threshold, the performance of an IFS will experience a substantial improvement and become more efficient. These results motivate consideration of an iFTS as an alternative option for future direct imaging space missions in the near-IR.
title Direct detection and characterization of exoplanets using imaging Fourier transform spectroscopy
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2310.15231