A Jupiter-size exoplanet has been discovered orbiting a tiny star and astronomers don't know how

Astronomers have discovered a Jupiter-size exoplanet orbiting a relatively small, low-mass star, challenging existing theories of planet formation. 

The exoplanet, named TOI-4860 b, orbits the red dwarf TOI-4860, which is located in the constellation of Corvus and has a mass equivalent to just around a third of the sun's. This discovery is surprising as planets of this size are not expected to form around low-mass stars.

TOI-4860 b, classified as a "warm Jupiter," completes an orbit approximately once every 1.5 Earth days. It is enriched with a high proportion of metals, a term astronomers use to describe elements heavier than hydrogen and helium. This discovery contradicts the canonical planet formation model, which suggests that the less mass a star has, the less massive is the disk of material around that star, and hence, high-mass planets like Jupiter were not expected to form.

TOI-4860 b was first spotted by NASA's Transiting Exoplanet Survey Satellite (TESS), and the sighting was followed up by observations from the Search for habitable Planets Eclipsing Ultra-cool Stars (SPECULOOS) South Observatory and the Subaru Telescope in Hawaii. The composition of TOI-4860 b hints at its origins, with the abundance of heavy elements likely acting as a catalyst to boost the planet's formation process.

The discovery of TOI-4860 b opens up new avenues for studying the atmospheres of warm Jupiters and better understanding how these gas giants are born. The team behind this discovery now plans to hunt for similar worlds around small parent stars using the Very Large Telescope (VLT) in Chile. This discovery is a significant step forward in deepening our understanding of planet formation.

Research Paper