An international team of planetary scientists has discovered for the first time a large “rogue planet” the size of Saturn in the central region of the Galaxy, located in the central region of the Milky Way and 9.9 thousand light years from Earth. Her discovery confirmed that in very rare cases, large planets can be ejected from their parent star systems, the researchers wrote in an article in the scientific journal Science.
“This object is included in the mass range of “rogue planets” that astronomers previously called “Einstein Deserts” due to the assumption that planets with masses significantly in excess of Earth's are very rarely ejected from stellar systems. Our discoveries to date are consistent with this theory – nine other known “rogue planets” have masses significantly lower than Neptune, the researchers wrote.
This discovery was made by a team of astronomers led by Director of the Warsaw University Observatory (Poland), Andrzej Udalski, as part of the OGLE project, which searches for gravitational microlensing created by nearby and invisible objects. As part of OGLE, astronomers have discovered a number of extremely dim and cold objects, commonly known as “rogue planets.”
Their exact origin and nature remain unclear. Some scientists believe they are large planets thrown out of their star systems by a series of complex gravitational interactions, while other researchers think they are actually small and very cool brown dwarfs, “failed” stars of extremely low mass.
Udalsky and his colleagues were able to clearly confirm for the first time that the signals recorded in OGLE were produced by ejected planets during observations of object KMT-2024-BLG-0792, located in the constellation Sagittarius at a distance of 9.9 thousand light years from Earth. Scientists took advantage of the fact that the object distorted the light output of a very massive red giant in the galactic core, which allowed them to determine the distance and size of the “rogue planet” using the GAIA orbiting observatory.
To do this, astronomers monitored how the star's position and brightness changed over several days during observations from Earth and from space, which allowed them to calculate the mass of the object – it turned out to be about five times smaller than Jupiter, making the “rogue planet” KMT-2024-BLG-0792 similar to Saturn. Astronomers concluded that this clearly showed that it originated within a protoplanetary disk and was then thrown out into the parent star system.
