Recent research published in The Astronomical Journal suggests that the next generation of advanced telescopes could revolutionize the hunt for potential extraterrestrial life by meticulously examining the atmospheres of nearby exoplanets. The study, conducted by a team of astronomers from The Ohio State University, focused on the capabilities of upcoming telescopes to detect chemical traces of oxygen, carbon dioxide, methane, and water on 10 rocky exoplanets—elements considered biosignatures also present in Earth's atmosphere, offering crucial evidence of life.
The findings of the study highlight the effectiveness of these advanced telescopes, such as the James Webb Space Telescope (JWST) and the Extremely Large Telescopes (ELTs), in detecting potential biosignatures on nearby exoplanets. Particularly noteworthy are Proxima Centauri b and GJ 887 b, where these telescopes demonstrate high proficiency in detecting the presence of biosignatures. While carbon dioxide could potentially be detected on Proxima Centauri b, no such capability was found for GJ 887 b. Although no exoplanet has been discovered to perfectly replicate Earth's early conditions for life, the study suggests that unique Super Earths—planets more massive than Earth but smaller than Neptune—could serve as promising targets for future research missions if examined more closely.
Direct imaging of exoplanets, employing techniques such as coronagraphs or starshades to block the host star's light, presents another avenue for astronomers. However, this method poses challenges in locating exoplanets and requires substantial time and effort. The researchers evaluated the ability of ELT telescopes, including the European Extremely Large Telescope, the Thirty-Meter Telescope, and the Giant Magellan Telescope, to handle this challenge. By testing the instruments' signal-to-noise ratio—the higher the ratio, the easier it is to detect and analyze a planet's wavelength—the researchers gauged their effectiveness in differentiating planetary noise from universal background noise while detecting biosignatures.
The results indicated that the Mid-infrared ELT Imager and Spectrograph of one of the European ELT instruments outperformed others in discerning the presence of methane, carbon dioxide, and water on select planets. Additionally, the High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph instrument showed potential in detecting methane, carbon dioxide, oxygen, and water, albeit requiring more exposure time.
Lead author Huihao Zhang emphasized the importance of simulations in providing insights into the capabilities and promises of these advanced telescopes. While not every planet may be suitable for direct imaging, the study underscores the potential of future missions in advancing the search for habitable planets and expanding our understanding of the universe.
Source: The Ohio State University