Tardigrade indexing approach on exoplanets

Area of Science:

• Astrobiology and Planetary Sciences
• Exoplanet Research
• Extremophile Biology

Background:

• Over 3800 exoplanets are known, presenting diverse environments for potential life.
• Tardigrades (water bears) are extremophiles studied for their resilience in harsh conditions.
• Assessing extraterrestrial habitability requires understanding organism survivability on other worlds.

Purpose of the Study:

• To establish a metric tool for evaluating tardigrade survivability on exoplanets.
• To determine the potential for active and cryptobiotic tardigrades on rocky-water and water-gas planets.
• To compare the habitability of selected exoplanets and solar system bodies for tardigrades.

Main Methods:

• Utilized the Planetary Habitable Laboratory - Exoplanet Catalog (PHL-EC) for exoplanet data.
• Calculated the geometrical means of six physical parameters (radius, density, escape velocity, etc.).
• Developed the Active Tardigrade Index (ATI) and Cryptobiotic Tardigrade Index (CTI) ranging from 0 to 1.

Main Results:

• Identified potential survivability metrics for tardigrades on 57 selected exoplanets and solar system bodies.
• Mars was indicated as potentially more suitable for tardigrades than other considered rocky planets.
• Sample exoplanets like Kepler-100d, Kepler-48d, Kepler-289b, TRAPPIST-1 f, and Kepler-106e were analyzed.

Conclusions:

• The developed metric provides a quantitative approach to assess exoplanet habitability for tardigrades.
• Mars presents a promising candidate within our solar system for tardigrade survival.
• Further research can expand this metric to other organisms and a wider range of exoplanets.