Technosignatures as a Path Towards Identifying Life Outside the Solar System

Abstract: The search for biosignatures on potentially habitable exoplanets has driven much of the recent planning in the exoplanet community for the next generation of space telescopes, and as our ability to characterize exoplanets improves, we also move closer to the direct detection of technosignatures on exoplanets. Though likely less common than biosignature signals, in many cases the clearly artificial nature of certain technosignatures would make their detection clearly indicative of life outside the Solar System. In the last few years serious thought has been given to the types of technosignatures one could reasonably expect to detect using current and next-generation observatories, giving a firm astrophysical foundation to this sub-field. I will summarize the immediate prospects for technosignature detection using JWST, and using a LUVOIR- or HabEx-like next generation space telescope. I will particularly focus on the possibilities of detecting industrial pollutants in exoplanet atmospheres, the emission from nightside city lights on exoplanets, and the spectroscopic signatures of advanced spaceflight. All three of these possible technosignatures now have detailed and physically-based expectations for their observability, and I will also discuss how non-detections can place meaningful upper limits on the frequency of technological life in the Solar Neighborhood.