The discovery of a strange planet that surprises scientists: a density close to iron and a thin atmosphere

Scientists have discovered an exoplanet called GJ 523b, which has an unprecedented density among rocky planets, reaching 7.8 grams per cubic centimeter, making it an exceptionally compact body. The planet's diameter is roughly twice that of Earth, but its mass is about 23 times that of our planet.

The planet orbits its star in approximately 17 and three-quarter days, and the planetary system is expected to be about 170 million years old, which is relatively young by cosmic standards. What surprises scientists even more is that this high density indicates a very thin atmosphere, even though its large size and enormous mass would have led, under normal circumstances, to attract large amounts of gases and form a thick atmosphere.

This planet was first observed by NASA's TESS satellite, and scientists then followed up their observations using the ground-based WIYN telescope at Kitt Peak National Observatory in Arizona. After combining the measurements, it turns out that the planet weighs 23.5 times the mass of Earth, while its radius is 2.55 times larger.

This discovery is considered a real scientific dilemma, as it raises a puzzling question about why this planet did not turn into a gas giant despite its enormous mass. Scientists put forward two main hypotheses: the first is that the planet lost its atmosphere due to intense stellar winds, and the second is that the planet resulted from a collision between two large planets.

Astronomers use the term "super-Earth" to describe such massive, rocky worlds, and they believe finding more similar examples will help understand planetary formation.