• Scientists studied the possible number of habitable exoplanets that could orbit a star
  • The scientists simulated systems with different sized stars and planets
  • Planets as big as Jupiter can affect the orbits of other planets

Scientists were able to calculate the maximum number of potentially habitable exoplanets in a star system. Their findings were based on various factors such as the type of host star in the system and the sizes of the planets orbiting it.

When it comes to finding exoplanets, astronomers first try to determine if they are orbiting their host star within its habitable zone. This is the region that’s not too far nor too close to the star. Orbiting within the habitable zone indicates that an exoplanet may have suitable environmental and atmospheric conditions to support life.

Recently, a team of scientists conducted a new study that focused on analyzing the maximum number of planets that can orbit a host star within its habitable zone. Their findings were presented in a new paper published in The Astronomical Journal.

One of the driving factors behind the study is the fact that Earth is the only habitable planet in the Solar System. Other star systems, however, have multiple potentially habitable exoplanets.

“This made me wonder about the maximum number of habitable planets it’s possible for a star to have, and why our star only has one,” astrobiologist Stephen Kane of the University of California, Riverside and lead author of the study said in a statement. “It didn’t seem fair!”

To solve this mystery, scientists created computer models of theoretical star systems. For these models, they created simulations of systems that have different sized stars and planets.

Using an algorithm, the scientists plotted the orbital trajectory of the planets around a host star based on their sizes. They discovered that the sizes of the planets played a key role in maintaining an orbit within the habitable zone.

According to the scientists, as long as a star system does not have a planet that’s as big as or bigger than Jupiter, which is the largest planet in the Solar System, then it could have about seven habitable exoplanets.

In the case of Earth’s neighborhood, the Solar System’s Sun could support about six planets with liquid water if Jupiter did not exist.

“More than seven, and the planets become too close to each other and destabilize each other's orbits,” Kane stated. “It has a big effect on the habitability of our Solar System because it's massive and disturbs other orbits.”

An illustrated model shows our solar system and its planets. NASA/JPL