In a groundbreaking discovery, astronomers have found a doomed planet that sheds an incredible amount of material—as much as a Mount Everest’s worth of mass with each orbit reports Space.com. This rare exoplanet, named BD+05 4868 Ab, is located about 140 light-years away in the Pegasus constellation. It orbits its star so closely—every 30.5 hours—that its surface is being scorched into magma, which then vaporizes into space. With each orbit, the planet leaves behind a blazing comet-like tail made up of molten rock, offering a rare look at an exoplanet in the final stages of its destruction.
The most astonishing part of this discovery is the sheer scale of the tail the planet leaves behind. According to Marc Hon, a postdoc at MIT’s Kavli Institute for Astrophysics and Space Research, “The extent of the tail is gargantuan, stretching up to 9 million kilometers long, or roughly half of the planet’s entire orbit.” The planet’s mass loss is so intense that it is expected to be completely disintegrated within 1 to 2 million years. “It’s like on its last breath,” says Avi Shporer, one of the collaborators on the study.
The Dying World: A Rare Discovery
The discovery of BD+05 4868 Ab adds to the small group of disintegrating exoplanets. Scientists have only identified a few such worlds among the more than 6,000 exoplanets discovered so far. While all of these planets leave behind a comet-like tail, BD+05 4868 Ab stands out for its massive size and the catastrophic scale of its evaporation. It has been observed that its tail is the longest of any disintegrating planet found to date, and experts believe that this planet is disintegrating much faster than others.The cause of this intense evaporation lies in the planet’s proximity to its host star. BD+05 4868 Ab orbits so close to its star that the intense heat causes its surface to vaporize at an alarming rate, releasing huge amounts of molten rock into space. This planet’s rapid disintegration presents an extraordinary opportunity for scientists to study the final stages of an exoplanet’s life cycle.
A Comet-Like Tail: A Rare Glimpse into a Planet’s End
The material being lost from BD+05 4868 Ab forms a comet-like tail, but it differs from traditional comets in that it doesn’t consist of volatile gases or ice. Instead, it is made of mineral grains evaporated from the planet’s rocky surface. These grains can linger long enough in space to form a tail that can be seen from Earth-based telescopes. As Marc Hon points out, this planet’s tail is a rare occurrence: “The shape of the transit is typical of a comet with a long tail, except that it’s unlikely that this tail contains volatile gases and ice as expected from a real comet.”
The discovery was made using NASA’s Transiting Exoplanet Survey Satellite (TESS), which detected a strange, fluctuating transit of the planet as it passed in front of its star. This anomaly led astronomers to suspect that they had discovered an unusual exoplanet, one that was shedding material at an extreme rate. The tail’s length and the planet’s rapid evaporation rate made it an ideal target for further observation, especially with NASA’s James Webb Space Telescope (JWST), which will be able to capture subtle changes in starlight and analyze the composition of the vaporized material.
The Unstable Planet: How Low Mass Contributes to the Destruction
Scientists believe that the planet’s low mass plays a crucial role in its rapid disintegration. Dr. Avi Shporer explains that “this is a very tiny object [between the size of Mercury and the moon], with very weak gravity, so it easily loses a lot of mass, which then further weakens its gravity, so it loses even more mass.” This process is described as a runaway effect, where the planet loses material at an accelerating rate, leading to its eventual destruction.
Such findings offer crucial insights into the life cycle of planets, especially in systems with extreme conditions. The study of BD+05 4868 Ab allows scientists to better understand the role of planetary mass and gravity in determining the longevity of a planet’s existence. The planet’s swift evaporation is a vivid reminder of how close a planet can come to destruction when it is subjected to intense heat and pressure from its host star.
