Opportunities for Technosignature Science in the Astro2020 Report

Brief

Haqq-Misra et al. (2022) systematically map nine categories of Astro2020 decadal survey recommendations onto specific technosignature search capabilities, spanning atmospheric pollution (NO2, CFCs), optical beacons, Dyson sphere waste-heat, and narrowband radio and X-ray signals. The paper quantifies key detection thresholds: a 15 m LUVOIR-like telescope could detect Earth-level NO2 at 10 pc in ~400 hours, JWST could detect CFCs in TRAPPIST-1e's atmosphere in ~100 hours at SNR ~3–5, and a probe-class far-IR mission like GEP would be three orders of magnitude more sensitive than IRAS for Dyson sphere searches. The authors do not propose new mission architectures but urge that technosignature science be written into the stated science cases of already-funded facilities, arguing this imposes zero marginal cost while offering potentially transformative returns.

Metadata

Category

Search

Venue

preprint (arXiv astro-ph)

Type

White paper

Year

2022

Authors

Jacob Haqq-Misra, Sofia Sheikh, Manasvi Lingam, Ravi Kopparapu, Adam Frank, Jason Wright

arXiv

2203.08968

Access

Open access

Length

163.2 K

Programs

NExSS, Astro2020 Decadal Survey

Instruments

LUVOIR, Roman Space Telescope, GMT, TMT, ngVLA, CMB-S4, JWST MIRI, GEP, DSA-2000, Cherenkov Telescope Array, IRAS, WISE, GBT, JVLA, VLBA

Tags

SETI, technosignature, biosignature, exoplanet-spectroscopy, Dyson-sphere, radio-SETI, CFC-detection, astrobiology, policy

Key points

• Astro2020 explicitly mentioned technosignatures in Appendices E-1 and M but not in the main report text; the paper argues the 'Are we alone?' framing of the 'Pathways to Habitable Worlds' program directly encompasses technosignature science.p.1
• A 15 m LUVOIR-like telescope could detect Earth-level NO2 (combustion indicator) for an exoplanet around a Sun-like star at 10 pc with ~400 hours of observation; K-dwarf targets require less time due to reduced photolytic NO2 loss.p.2
• The Roman Space Telescope could detect a 7.3 W laser within τ Ceti's habitable zone, implying that low-powered optical beacons are within reach of the recommended ~6 m IR/O/UV flagship for most rocky-planet characterization targets.p.3
• Dyson sphere waste heat around a Sun-like star at 1 AU peaks at ~7 μm; a far-IR probe like GEP (24–193 μm) would be three orders of magnitude more sensitive than IRAS and could sharply reduce protoplanetary disk confusion.p.4
• CFCs have no known abiotic or non-technological biological formation pathway and have residence times of ~10 to ~10^5 years; CFC-11 absorbs at 11.7 μm, and JWST could detect current or historic CFC levels in TRAPPIST-1e's atmosphere in ~100 hours at SNR ~3–5.p.5
• Narrowband X-ray emission at 0.5–2 keV has been proposed as the optimal ETI communication channel based on data-rate maximization; a km-sized impactor on a neutron star would produce an ~10^29 W X-ray pulse detectable across the Milky Way.p.5
• The ngVLA (244 antennas, 1.2–116 GHz, order-of-magnitude sensitivity gain over JVLA/VLBA) would enable commensal technosignature limits on millions of targets including stars, galaxies, and solar system objects, while astrometric orbital motion within ~100 pc provides an RFI discriminant.p.6
• CMB-S4 (30–270 GHz, every-other-day cadence, ~50% sky coverage) would constitute the first systematic technosignature search at frequencies higher than any prior radio/microwave SETI program.p.7

Verbatim

• “life's global impacts on a planet's atmosphere, surface, and temporal behavior may therefore manifest as potentially detectable exoplanet biosignatures, or technosignatures”

  p.1

• “Kopparapu et al. (2021) found that a 15 m LUVOIR-like telescope could detect Earth-like levels of NO 2 for a planet around a Sun-like star at 10 pc with ∼ 400 hours of observation, while planets orbiting K-dwarf stars would require even less time due to the reduction in loss of NO 2 from photolysis in such systems.”

  p.2

• “the emission from a Dyson sphere around a Sun-like star situated at a distance of 1 AU is predicted to peak at roughly 7 μm”

  p.4

• “a probe-class mission like the GEP would be three orders of magnitude more sensitive than IRAS and would likewise represent a substantial advance in sensitivity compared to WISE”

  p.4

• “Technosignature science will likely add no additional expense to such projects, and the science returns of finding technosignatures could be tremendous.”

  p.9

Most interesting

• A 7.3-watt laser, less power than a standard LED bulb, would be detectable by the Roman Space Telescope within τ Ceti's habitable zone, according to Vides (2019).
• CFCs are the only class of atmospheric constituents with no known abiotic or biological non-technological formation pathway, making them the conceptually cleanest technosignature in transit spectroscopy.
• CFC residence times spanning ~10 to ~100,000 years mean a far-IR probe could, in principle, detect the atmospheric legacy of a civilization that ceased industrial activity millennia ago.
• Technosignature search software produces the finest frequency-resolution microwave data of any astronomical instrumentation, making it a natural byproduct source for publicly accessible RFI catalogs, a concrete benefit the paper uses to justify commensal backend funding.
• The paper proposes that a km-sized rock impacting a neutron star could produce an X-ray burst of ~10^29 W, sufficient to be detected across the entire Milky Way, as a low-cost ETI signaling mechanism requiring no specialized transmitter.
• The Astro2020 decadal survey's recommended ~6 m IR/O/UV telescope aperture was sized for a 'robust sample of ~25 atmospheric spectra of potentially habitable exoplanets,' a sample large enough to statistically constrain atmospheric technosignature prevalence as a byproduct.