US Astonomers from the Carnegie Institution have recently spotted a rare astronomical occurrence that has not been seen before -- twin stars hosting three exoplanets. This marks the first exoplanet detection made based solely on data from the Planet Finder Spectrograph.

According to the findings published in the Astrophysical journal, the stars, which are practically siblings of the sun are named HD 133131A (hosting the two planets) and HD 133131B (hosting the third).

Dr. Johanna Teske who led the study notes that the two stars are the closest in a binary system. CNN said that the shortest previous distance between two stars in a binary system hosting planets was 1,000 AU. HD 133131A and HD 133131B, however, has a distance of 360 AU.

Aside from the close stance, the astronomers also observed that the exoplanets they are hosting are Jupiter-sized.

According to a press release published on the Carneige Science website, these finding particularly interests scientists as they believe the influence of giant planets shape the solar system's architecture, noting that the lack of Jupiter-sized planet in our system explain why our is different from the other systems observed.

"We are trying to figure out if giant planets like Jupiter often have long and, or eccentric orbits," Teske explained. "If this is the case, it would be an important clue to figuring out the process by which our Solar System formed, and might help us understand where habitable planets are likely to be found."

Another interesting finding is that instead of heavy elements found in average stars, the twin stars are mainly composed of hydrogen and helium.

"This is important for planet formation because we think some minimal amount of solid material is needed in a protoplanetary disk, where planets form around a star, to make giant planets quickly enough, before the gas disperses and the giant planet cores can accrete enough gas to become giants," Teske said in an interview with CNN.

Despite having similar size and brightness to the sun, the twin stars are not identical twins as previously thought, rather they are fraternal because they have slightly different composition.