Researchers find exoplanet orbiting its star in reverse

An international team has found a planet orbiting a cool red dwarf in the opposite direction to the star’s rotation, ERR reported. The planet, GJ 3090 b, has a radius slightly more than twice that of Earth.

Researchers from Switzerland, the United Kingdom, Canada and other countries studied the system using powerful spectrographs in Chile. By analysing how the planet’s movement obscures the star’s surface, they calculated the angle of its orbit.

The planet’s orbit is inclined by 136 degrees relative to the star’s rotation axis, making it one of the most strongly tilted orbits discovered so far. The system also contains at least one other confirmed planet and a second possible planet.

Strongly tilted orbits have been found in other systems, but those have included a massive giant planet or a nearby star whose gravity could disrupt the smaller bodies’ movements. Researchers found no evidence of either in this system.

They suggest GJ 3090 b may have formed on its tilted orbit. After the original star system formed, the young star may have gathered new gas and dust, creating a material disk strongly inclined to the star’s rotation. Planets formed in that disk may then have migrated to their current positions while retaining their unusual orientation.

The findings were published in the journal Astronomy & Astrophysics.