Red Dwarfs Are Too Dim to Generate Complex Life
6 days ago
- #Red Dwarfs
- #Great Oxygenation Event
- #Exoplanet Habitability
- The Great Oxygenation Event (GOE) was a pivotal moment in Earth's history, occurring around 2.3 billion years ago when photosynthetic cyanobacteria released oxygen into the atmosphere.
- Complex life on Earth depends on aerobic respiration, which requires significant oxygen levels, a process that took about 2.5 billion years to develop.
- Red dwarfs (M dwarfs) are the most common stars in the Milky Way and host many rocky, Earth-like exoplanets, raising questions about their potential to support life.
- New research explores whether red dwarfs emit enough radiation for photosynthesis to trigger a GOE on their orbiting planets, focusing on the TRAPPIST-1 system.
- TRAPPIST-1e, an Earth-like exoplanet in the habitable zone of its star, receives only 0.9% of the Photosynthetically Active Radiation (PAR) Earth gets, making a GOE unlikely within the current age of the universe.
- Non-oxygenic photosynthetic bacteria, which require less light and can use near-IR wavelengths, might dominate red dwarf exoplanets, preventing oxygen accumulation and complex life.
- The study concludes that complex life is unlikely on planets orbiting late M-dwarfs due to insufficient stellar radiation, even if other habitability factors are favorable.
- Future discoveries of oxygen in red dwarf exoplanet atmospheres would challenge current assumptions and indicate novel biological processes.