Scientists have discovered a planet that is larger than expected in comparison to its smaller host star.

The planet is 13 times larger than Earth and it is circling around a star known as LHS 3154, which is only nine times the size of the sun. While the planet’s size is not extraordinary, its connection with an ultracool dwarf star, one of the tiniest and coolest stars in the cosmos, has left researchers perplexed.

The unlikely duo’s mass ratio is 100 times greater than that of the Earth and the sun, which greatly exceeds the expected limit according to current theories on planet formation.

According to Professor Suvrath Mahadevan from Penn State University, who co-authored the research published in the journal Science, this finding emphasizes the fact that our understanding of the universe is limited. It is surprising to find a planet of this size orbiting a star with such low mass.

Stars are created when massive clouds of gas and dust cool down and collapse due to their own gravitational pull. As the star begins to spin, the remaining gas and dust transforms into a flat disk, similar to dough being shaped into a pizza. Over time, the material in the disk can come together to create planets.

The quantity of material that can contribute to the formation of planets is believed to be proportional to the size of the star it orbits.

According to Mahadevan, the disk of material that forms planets around the small star LHS 3154 does not contain enough solid material to produce this particular planet. However, the existence of this planet challenges our current understanding of the formation of planets and stars.

The scientists discovered a large planet called LHS 3154b with the help of the Habitable Zone Planet Finder (HPF). This device is capable of detecting slight changes in the light of faraway stars, indicating the presence of a planet in orbit.

The purpose of the system is to identify planets that orbit around the coldest stars beyond our solar system and have the potential to sustain liquid water on their surfaces, which is necessary for life as we understand it.

Although it is challenging to identify such planets orbiting stars similar to our sun, the cooler temperature of ultracool stars allows for the possibility of liquid water on planets located closer to their star than Earth is to the sun. A study of LHS 3154 found that it is in close proximity to its host star, with an orbital period of only 3.7 days.

Mahadevan compared the star to a campfire, explaining that as the fire cools, one must get closer to it to stay warm. This concept also applies to planets, as a colder star means a planet must be closer in order to maintain liquid water.

Professor Frédéric Masset from the National Autonomous University of Mexico commented on the results, stating that discovering a planet of this size near a small star is unprecedented and could potentially change our understanding of how planets are formed.

It is possible that planetary disks contain a significantly larger amount of dust than originally believed.

Source: theguardian.com