Astronomers have spotted a planetary system that challenges current theories on planet formation, as it contains a rocky planet that formed outside the orbits of its gaseous neighbors, possibly after most of the material needed to form planets was exhausted. The system, observed using the European Space Agency's CHEOPS space telescope, consists of four planets—two rocky and two gas giants—orbiting a relatively small and faint red dwarf known as LHS 1903, about 117 light-years from Earth in the constellation Lynx. Researchers believe the planets in this system did not form all at once in a large disk of gas and dust orbiting its host star but formed sequentially, where sibling gas planets consumed the gas that was supposed to form the atmosphere of the fourth planet before it could coalesce. Wilson, lead author of the study published in Science, stated: 'The fourth planet was likely one of the planets that formed in later stages.' Dwarf rocky planets like Pluto, which orbit outside gas giants, are much smaller than any planet in our solar system. Since the 1990s, astronomers have discovered about 6,100 exoplanets, planets outside our solar system. In contrast, it is believed that planets far from their stars form in cooler regions rich in gas and ice, creating gas-rich worlds with thick atmospheres. Future observations with the James Webb Space Telescope could reveal conditions on this planet and help us understand its habitability. The closest planet to the star is rocky, the next two are gas giants, and the fourth, which current planet formation theories suggest should be a gas giant, is also rocky. Wilson added: 'A temperature of 60 degrees Celsius is very similar to the highest temperature recorded on Earth, which was 57 degrees, so it is certainly possible that this planet is habitable.' In our solar system, the four inner planets are rocky and the four outer planets are gaseous. This system defies this theory, presenting us with a rocky planet outside the gas-rich zone.'
