70 Ophiuchi and 36 Ophiuchi binary systems show potential for supporting stable habitable planets

Star system: 70 Ophiuchi A | Distance from the Sun: 16.7 light years

Numerical simulations have evaluated whether planets in the 70 Ophiuchi, 36 Ophiuchi, and Gamma Leonis binary systems can remain stable in their habitable zones. The habitable zone is the range of distances from a star where conditions might allow liquid water to exist on a planet's surface. While Gamma Leonis is unlikely to support stable planets due to its extreme orbital dynamics, the 70 Ophiuchi and 36 Ophiuchi systems show promising conditions for long-term planetary stability.

Researchers modeled planetary orbits within these binary systems to track how gravitational interactions with the two stars affect potential planets over time. They specifically looked at how orbital alignment—whether a planet orbits in the same plane as the two stars or at an angle—influences the stability and climate of a planet.

The study found that planets orbiting in the same plane as the binary stars are highly stable, facing uninhabitable conditions less than 2% of the time. However, planets with orbits tilted by 45 degrees relative to the binary plane experience larger changes in their orbital eccentricity, or the shape of their path around the star, leading to higher instability rates of nearly 5%.

Key findings
- 70 Ophiuchi and 36 Ophiuchi are viable targets for future missions searching for habitable worlds.
- Gamma Leonis is unlikely to host habitable planets due to severe gravitational instability.
- Planets coplanar with the binary star orbits remain habitable nearly 98% of the time.
- Misaligned orbits at 45 degrees increase the risk of planetary habitability loss to about 5%.
- Binary star gravitational interactions remain a critical factor in determining long-term planetary climate stability.

Scientific study

Assessing Planetary Stability and Long-Term Habitability in Nearby Stellar Binaries: 70 Oph, 36 Oph, γ Leo (external link)