Why land detection is critical for confirming exoplanetary life

How can the identification of land on exoplanets help scientists better understand if an exoplanet could nourish life? This is what a recently subject study hopes to approach as a researchers’ team has studied how land identification on exoplanets could help dispel the false positives of the world of water, which occur when the data indicate that an exoplanet contains deep oceans (around 50 terrestrial oceans), hence the name “waterworld”. This study, published on the arxiv Preprint Server has the potential to help scientists develop more effective methods to classify exoplanets and their compositions, in particular to know if they contain life as we know it, or even if we do not know.

For the study, the researchers analyzed the spectral data obtained from the spectral library of the United States Geological Survey (USGS), with the exception of the sand of the desert and the ice. The objective of the study was to determine whether the proposed next generation space telescope, the observatory of habitable worlds (HWO), would be able to detect the land masses on rocky exoplanets. In the end, the researchers determined that Hwo would need a telescope size of approximately 8 meters (26 feet) to detect the terrestrial masses based on signal / noise data (SNR) in visible and ultraviolet wavelengths, while building a case for HWO capacities to detect oxygen biosincatures.

The study notes in its conclusions: “Land detection via reflected light spectroscopy can help exclude o₂ False positive biosignature associated with the removal of o₂ flows due to extremely deep oceans. Land detection is possible because all probable terrestrial surfaces for exo-land analogues have a positive sloping reflectance spectrum in the visible, while liquid water and ice / water snow are flat or slopes negatively. “”

As indicated, HWO is a mission of the next generation space telescope proposed aimed at being the most powerful space telescope built which succeeds the James Webb space telescope of NASA (JWST). HWO’s planned capacities include imaging objects in optical, infrared and ultraviolet wavelengths, its main objective being to directly imagine a minimum of 25 habitable exoplanets. Although Hwo is not planned to get started before the 2040s, scientists and engineers continue to develop the technologies necessary for HWO to end its mission and identify a habitable world beyond Earth.

Current candidates of exoplanets in the world of water include exoplanets (and distances of the earth) in Trappist-11 (40 light years) and Kepler-11 (2110 light years), as well as Kepler-62e (1,200 light years), Kepler-62F (1,200 years-light), Kepler-22B (587 old) and GJ 1214b (40 years (40 years. Light years). More recently, a study in 2024 published in Astrophysical newspaper letters Announced by JWST had discovered a “vapor world” identified as GJ 9827D, which resides around 97 light years from the earth and whose radius is slightly less than two lands. What makes GJ 9827D intriguing is that if its atmosphere is made up of steam, the planet itself is estimated too hot to support life as we know it.

Although the number of waterworld exoplanets is currently limited, this recent study occurs the number of confirmed exoplanets within our milky galaxy quickly approaches 6,000, which currently includes 219 terrestrial exoplanets (rocky) and 1,746 super-terre as GJ 9827D. While JWST is powerful enough to analyze the compositions of the exoplanet atmosphere, Hwo could start a new era in the discovery and exploration of exoplanets by directly imagining the habitable worlds and potentially discovering an exoplanet capable of supporting life as we know it, or even if we do not know it.