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Exoplanet GJ 3090 b Orbits Opposite Its Star
Confirmed
In Short: An international team led by the University of Geneva (UNIGE) has discovered that the exoplanet GJ 3090 b orbits its star in the opposite direction to the star's rotation.
The planet was first detected by NASA's TESS space telescope in 2022, which identified it through transits—small, periodic variations in a star's brightness caused by a planet passing in front of it.
Using the NIRPS infrared spectrograph, the team confirmed the unique orbit of GJ 3090 b, which is highly misaligned and orbits in the opposite direction to its star.
GJ 3090 b is a Neptune-sized planet with a radius 2.2 times that of Earth and a mass 4.5 times that of Earth.
The discovery challenges the conventional understanding of planetary system formation, where a star and its planets typically rotate in the same direction since they form from the same disk of gas and dust.
Andrew Winter, an astrophysicist at Queen Mary University and lead author of the study, stated, “This is a remarkable planetary system because the planet is not simply tilted relative to its star—it is orbiting in the opposite direction. That immediately raises the question of how such an unusual orbit could have formed.”
Vincent Bourrier, an astronomer at the University of Geneva, added, “The idea that a planetary system could be rebuilt from a second, differently oriented disk is particularly exciting. It suggests that the environment around a young star can play a much bigger role in determining the architecture of its planets than we might have expected.”
The study, published in Astronomy and Astrophysics, offers new insights into the evolution of planetary systems and the complex dynamics that can shape their orbits.
GJ 3090 b is located about 73 light-years from Earth, making it a relatively close exoplanet for study.
What's confirmed
- The planet was first detected by NASA's TESS space telescope in 2022, which identified it through transits—small, periodic variations in a star's brightness caused by a planet passing in front of it.
- Using the NIRPS infrared spectrograph, the team confirmed the unique orbit of GJ 3090 b, which is highly misaligned and orbits in the opposite direction to its star.
- GJ 3090 b is a Neptune-sized planet with a radius 2.2 times that of Earth and a mass 4.5 times that of Earth.
- The discovery challenges the conventional understanding of planetary system formation, where a star and its planets typically rotate in the same direction since they form from the same disk of gas and dust.
- The study, published in Astronomy and Astrophysics, offers new insights into the evolution of planetary systems and the complex dynamics that can shape their orbits.
- GJ 3090 b is located about 73 light-years from Earth, making it a relatively close exoplanet for study.
What's still developing
- The cloud then forms a disc around the nascent star, within which the planets will form.
- Read More: 5 of the Strangest and Most Dangerous Exoplanets Ever Discovered Planetary systems form when a cloud of gas and dust collapses in on itself.
- The cloud spinning around the star then flattens into what’s called a protoplanetary disk, and it’s within this disk that planets are born.
- While planets generally orbit in the same direction as their host star, this one is an outlier: It travels around its star in the opposite direction to the star’s rotation, leaving astronomers bewildered.
- First, the material collapses toward the center and forms the star.