Scientists have discovered that Earth sized exoplanets orbit their parent star just like our planets orbit the sun, would help them to zero in on planets most likely to harbor extraterrestrial life.

It was a debate whether our solar system was a special case or it is a common norm for all the planets to orbit around that parent star and at same distance.

Scientists are from the MIT and Denmark’s Aarhus University.

Scientists for the study have examined orbits of 74 exoplanets travelling around 28 stars.

Vincent Van Eylen, a visiting graduate student in the MIT Department of Physics said, “Twenty years ago, we only knew about our solar system, and everything was circular and so everyone expected circular orbits everywhere. Then we started finding giant exoplanets, and we found suddenly a whole range of eccentricities, so there was an open question about whether this would also hold for smaller planets.”

The scientists have determined roughly equidistant circular orbits, and believe that the norm is followed in at least the systems with planets as small as the Earth.

Researchers have first created the hypothetical orbits of planets around parent star with predetermined characteristics, based on the assumption of circular orbits.

Then the researchers have used the NASA’s Kepler space telescope to determine the actual orbital periods of the planets, and they found that it matched with the predicted models, confirming that their orbits were circular and regular.

Giant exoplanets are in contrast to the Earth sized bodies, as they orbit in eccentric orbits, which bring them very close to the host star and then take them very far from it.

This discovery is going to have an effect on the search for extraterrestrial life, as Earth sized exoplanets have stable orbit around their host star which means that the conditions on those planets are likely to remain stable and steady over time.

Van Eylen says an earth sized planet compact enough to consist mostly of rock, as opposed to consisting mostly of gas, as with giant exoplanets, in regular circular orbit around its star would result in stable climate all through the planets year that could make it hospitable to life.

He added, “If eccentric orbits are common for habitable planets, that would be quite a worry for life, because they would have such a large range of climate properties, but what we find is, probably we don’t have to worry too much because circular cases are fairly common.”