Model of the Search for Extraterrestrial Intelligence with Coronagraphic Imaging

Abstract

We present modeled detection limits of the Gemini Planet Imager (GPI) and the Wide-Field Infrared Space Telescope (WFIRST) to an optical and infrared laser which could be used by an extraterrestrial civilization to signal their presence. GPI and WFIRST could utilize a coronagraph to search for extraterrestrial intelligence (SETI) in the present and future. We use archival data for GPI stars and simulated WFIRST observations to find the detectable flux ratio of a laser signal to residual scattered starlight around the target star. This flux ratio is then converted to detectable power as a function of distance from the parent star. For GPI, we assume a monochromatic laser wavelength of 1.55 µm and a wavelength of 575 nm for WFIRST. We assume the lasers are projected through a 10-m aperture, and that the intensity of the laser beam follows a Gaussian profile. Our analysis is performed on 6 stars with spectral types later than F within 20 pc (with an emphasis on solar analogs at different distances). The most notable result is the detection limit for τ Ceti, a G5V star with four known exoplanets, two of those within the habitable zone (HZ). The result shows that a 24 kW laser is detectable from τ Ceti from outside of the HZ with GPI and a 7.3 W laser is detectable from within τ Ceti's HZ by WFIRST.

Searching for technosignatures in exoplanetary systems with current and future missions

“…Note that we include all ground-based instrumentation in the ground-based photometry and ground-based spectroscopy categories, although specific observatory-instrument combinations may only access a subset of indicated technosignatures. For example, the Gemini Planet Imager (GPI) could plausibly detect optical beacons [79], but no other indicated technosignatures. See text accompanying Sections 3, 4, 5, and 6 for more specific examples of current, future, or potential ground-based facilities capable of detecting the indicated technosignatures.…”

“…The next-generation space-based observatories the Infrared/Optical/Ultraviolet space telescope and Nautilusand possibly HST and JWST -could provide further constraints on the presence of optical beacons in exoplanet systems. Vides et al [79] have produced predictions for the Gemini planet Imager (GPI) and RST. Their work predicts observational capabilities for a continuous laser signal for both observatories and determine that 24 kW (GPI) 7.3 W (RST) signals would be detectable from the 𝜏 Ceti system.…”

Searching for technosignatures in exoplanetary systems with current and future missions

“…Note that we include all ground-based instrumentation in the ground-based photometry and ground-based spectroscopy categories, although specific observatory-instrument combinations may only access a subset of indicated technosigatures. For example, the Gemini Planet Imager (GPI) could plausibly detect optical beacons [79], but no other indicated technosignatures. See text accompanying sections 3, 4, 5, and 6 for more specific examples of current, future, or potential ground-based facilities capable of detecting the indicated technosignatures.…”

“…The nextgeneration space-based observatories the Infrared/Optical/Ultraviolet space telescope and Nautilus-and possibly HST and JWST-could provide further constraints on the presence of optical beacons in exoplanet systems. Vides et al [79] have produced predictions for the Gemini planet Imager (GPI) and RST. Their work predicts observational capabilities for a continuous laser signal for both observatories and determine that 24 kW (GPI) and 7.3 W (RST) signals would be detectable from the τ Ceti system.…”

Direct Exoplanet Detection using Convolutional Image Reconstruction (ConStruct): A New Algorithm for Post-processing High-contrast Images

“…These methods are effective for finding companions at close separations to their host stars, but are less sensitive at wider orbital distances. Over the past two decades, high-contrast imaging (HCI) has emerged as an effective tool to study long-period planets by probing the architectures of planetary systems from the outside in, while also enabling spectroscopic characterization of their atmospheres (Bowler 2016;Baron et al 2019;Nielsen et al 2019;Vigan et al 2021).…”