The discovery of a new planet challenges theoretical models of planet formation. The planet is far too big for its star, according to a new study by an international research team with Swiss participation.

The newly discovered planet, which orbits a so-called M-dwarf star called LHS 3154 with a 3.7-day orbit, is about 13 times more massive than Earth, according to the study published Thursday in the journal Science.

“Such a star, only 0.11 times the mass of the Sun, has never been observed before," wrote astronomer Frédéric Masset of the National University of Mexico in a commentary on the study published in the same journal.

According to the study's authors, including a researcher from the Swiss Federal Institute of Technology Zurich (ETHZ), current theories of planet formation cannot explain how such a massive planet could have formed around LHS 3154.

An M dwarf star is the smallest and coolest type of star. The theories say that M dwarfs do not produce particularly large planets. Stars form from large clouds of gas and dust. The material left over from the star formation process forms a disc around the star in which planets are later born.