New Delhi: For the first time, astronomers have confirmed a candidate rogue planet as a planet. These wayward worlds have been kicked out from their origin
systems by gravitational interactions. The planet was confirmed because of a lucky alignment of space and ground-based telescopes that allowed researchers to determine the mass of a rogue planet for the first time. Over the past decade, telescopes have collected fleeting observations of about a dozen rogue planet candidates. The only way to detect these wandering worlds is through a phenomenon known as microlensing, which requires the planet to pass in front of a distant background star.
During such passages, the gravitational influence of the rogue planet briefly bends and amplifies the light from the distant star, creating a flicker of brightness. Such fleeting glimpses provide little information about the worlds themselves. For the new study, an international team of astronomers determined the mass of a rogue planet candidate for the first time. The object contains about a fifth the mass of Jupiter, which is comparable to the mass of Saturn, dispelling any doubts about its planethood. While past detections have hinted that microlensing objects can vary in mass from small, rocky worlds to gas giants, scientists had to work with indirect guesstimates so far. A paper describing the research has been published in Science.
More rogue planet discoveries expected
The observations lend support to long-running microlensing surveys and theoretical models that suggests that the Milky Way galaxy hosts a population of billions, or even trillions of starless planets. The world was confirmed through a microlens parallax effect, similar to depth perception in humans. This technique will be useful in the next generation of microlensing surveys. The concept of rogue worlds has entered popular consciousness because of the 2019 blockbuster Chinese movie The Wandering Earth, which is based on a short story by Cixin Liu, where the whole world comes together to build a gigantic rocket array to propel Earth out of its orbit to avert certain doom.
