Simulations suggest Earth-sized planet could stably orbit in habitable zone of binary star system 70 Ophiuchi

By the Everything Space news desk · 03 Oct 2026 · written from the sources below

Image: Phys.org

The modeling work hints that two-star systems, long assumed hostile to stable planets, may still host worlds capable of supporting liquid water.

Researchers studying the binary star system 70 Ophiuchi have found that an Earth-mass planet could theoretically maintain a stable orbit within the system's habitable zone, the region around a star where conditions might allow liquid water to persist on a planet's surface. No planets have yet been confirmed around either star in the system, but the new analysis suggests such a world could exist without being torn apart by the gravitational pull of the second star.

70 Ophiuchi lies about 5 parsecs from Earth, making it one of the closer star systems to our own, though still trillions of miles away. It consists of two stars slightly smaller and cooler than the sun, with masses of roughly 88% and 73% of the sun's mass. Despite decades of observation, the system's planetary status has remained unclear.

To investigate, scientists used updated observational data from the University of Michigan describing how the two stars move around each other. This allowed them to build a more precise model of the system's structure. A doctoral student at the University of California, Riverside then ran simulations placing a hypothetical Earth-mass planet at various distances from the larger star to see whether its orbit would remain stable, become elongated, or result in the planet being ejected or pulled into a star.

The simulations showed that stable orbits were possible within the habitable zone of the primary star, despite the presence of a second star nearby. This challenges the assumption that companion stars necessarily disrupt the orbits of potentially habitable planets.

According to the researchers, most stars in the galaxy have companions, unlike the sun, so understanding how planets can remain stable in such multi-star systems is important for broader searches for habitable worlds. They noted that exoplanet discoveries over recent decades have shown planetary systems can differ greatly from our own, meaning habitable worlds might not resemble Earth's neighborhood.

The team suggested that this kind of dynamical modeling could help prioritize targets for NASA's planned Habitable Worlds Observatory, a mission intended to search for potentially habitable planets starting in the 2040s. They noted that many other binary systems could benefit from similar analysis before telescopes attempt direct observations.

While no planet has yet been detected around 70 Ophiuchi, the researchers said it remains possible that one could be found in the predicted habitable zone before the observatory even launches.

Written in Everything Space’s own words by our news-desk model from the sources above, and checked against them in code: every number in this report appears in its sources, and no sentence is copied from them.