Latest news with #BD+05
Malay Mail
23-04-2025
- Science
- Malay Mail
Planet on the edge: Disintegrating world with dusty tail offers rare glimpse into exoplanet death spiral
WASHINGTON, April 24 — Astronomers have spotted a small rocky planet that orbits perilously close to its host star disintegrating as its surface is vaporised by stellar heat, trailed by a comet-like tail of mineral dust up to about 9 million km long. About 5,800 planets beyond our solar system, called exoplanets, have been discovered since the 1990s. Of those, only four have been observed disintegrating in orbit, as this one is. This planet is the closest to our solar system of the four, giving scientists a unique opportunity to learn about what happens to these doomed worlds. The researchers observed the planet, named BD+05 4868 Ab, as it gradually crumbles into dust, shedding material roughly equal to the mass of Mount Everest with each orbit of its star. The tail of dust trailing the planet wraps halfway around the star. The planet is estimated as between the size of our solar system's smallest and innermost planet Mercury and Earth's moon. It is located about 140 light years away from Earth in the constellation Pegasus. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). Its host star, a type called an orange dwarf, is smaller, cooler and dimmer than the sun, with about 70 per cent of the sun's mass and diameter and about 20 per cent of its luminosity. The planet orbits this star every 30.5 hours at a distance about 20 times closer than Mercury is to the sun. The planet's surface temperature is estimated at close to about 1,600°Celsius thanks to its close proximity to its star. As a result, the planet's surface has probably been turned to magma — molten rock. 'We expect the planet to disintegrate into dust within the next million years or so,' said Marc Hon, a postdoctoral researcher at the Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research and lead author of the study published on Tuesday in the Astrophysical Journal Letters. 'This is catastrophically quick in cosmic timescales. The disintegration is a runaway process. As more material from the planet turns into dust, the disintegration process gets faster,' Hon said. Once in space, the vaporised material cools down to form mineral dust that streams away from the planet. 'We know the dust grains in the tail can have sizes between large soot particles and fine grains of sand,' Hon said. 'We don't know the mineral composition of the tail yet.' The researchers detected BD+05 4868 Ab using the 'transit method,' observing a dip in the host star's brightness when the planet passes in front of it, from the perspective of a viewer on Earth. It was found using Nasa's Transiting Exoplanet Survey Satellite, or TESS, space telescope. How the planet came to have its current close-in orbit is unclear. 'The planet's orbit is not seen to be visibly decaying from the data. It is possible that the planet initially formed farther away, and had its original orbit altered under the influence of an external body, such that the planet was sent much closer to the star,' Hon said. This could have resulted from the gravitational influence of another planet or some other celestial object. The researchers plan further observations in the coming months using Nasa's James Webb Space Telescope to study the composition of the material in the tail, which could give clues about the makeup of rocky exoplanets. The search for life in other solar systems focuses on rocky exoplanets orbiting stars in the 'habitable zone,' a distance where liquid water, a key ingredient for life, can exist on a planetary surface. 'The tail is expected to contain minerals evaporated from the surface or interior of the disintegrating planet. So, this could be the crust, mantle or even the planet's core. Learning about the interiors of planets is extremely challenging. Doing this even for planets within our solar system is difficult. But BD+05 4868 Ab will allow us to directly measure the mineral composition of a terrestrial planet outside our solar system,' Hon said. 'This is definitely an exceptional opportunity for exoplanet geology and to understand the diversity and potential habitability of rocky worlds beyond our solar system,' Hon said. — Reuters
Yahoo
22-04-2025
- Science
- Yahoo
Astronomers discover doomed planet shedding a Mount Everest's worth of material every orbit, leaving behind a comet-like tail
When you buy through links on our articles, Future and its syndication partners may earn a commission. Scientists have discovered a planet that is literally falling apart as it orbits its star. Located about 140 light-years from Earth in the Pegasus constellation , this doomed world named BD+05 4868 Ab whips around its star once every 30.5 hours — so close that its surface is being scorched into magma and vaporizing into space. With each orbit, BD+05 4868 Ab leaves a blazing trail of molten rock behind it like a comet made of lava, offering a rare glimpse of an exoplanet in the final stages of its destruction. What's even more astonishing: with every blistering 30-hour orbit — which heats the planet to close to 3,000 degrees Fahrenheit (1,600 degrees Celsius) — the planet sheds as much mass of molten rock as an entire Mount Everest. "The extent of the tail is gargantuan, stretching up to 9 million kilometers long, or roughly half of the planet's entire orbit," said Marc Hon, a postdoc in MIT's Kavli Institute for Astrophysics and Space Research in a statement. This is an epic disintegration unfolding in real time, and the team predicts that it might take 1 to 2 million years for the entire planet to fully disintegrate. "We got lucky with catching it exactly when it's really going away," said Avi Shporer, a collaborator on the discovery who is also at the TESS Science Office. "It's like on its last breath." Only three other disintegrating worlds have been identified among the more than 6,000 discovered exoplanets — each leaving a distinctive, comet-like tail of debris behind it. But BD+05 4868 Ab stands out: its tail is the longest of them all. "That implies that its evaporation is the most catastrophic, and it will disappear much faster than the other planets," Hon said. Because BD+05 4868 Ab orbits so perilously close to its star, its transit — the dip in starlight created as the planet passes in front of its star — appears especially bright and distinct. The planet was discovered with NASA's Transiting Exoplanet Survey Satellite (TESS) observatory. TESS, which scans nearby stars for periodic dips in brightness, revealed a strange, fluctuating transit that stood out from the usual planetary candidates. This makes it an ideal target for NASA's James Webb Space Telescope, whose sensitive instruments can capture subtle changes in starlight to identify the chemical makeup of the vaporized rock trailing behind the planet. The result is a rare opportunity to watch a planet disintegrate in real time, and to study the composition of a world being stripped down to its core. Hon says the discovery was a lucky break. "We weren't looking for this kind of planet," he explained. "We were doing the typical planet vetting, and I happened to spot this signal that appeared very unusual." Though BD+05 4868 Ab's transit appears every 30.5 hours, the star's brightness took much longer than in other instances to return to normal. Even more bizarre was the depth the starlight's dip changed with every transit. "The shape of the transit is typical of a comet with a long tail," Hon explained. "Except that it's unlikely that this tail contains volatile gases and ice as expected from a real comet — these would not survive long at such close proximity to the host star. Mineral grains evaporated from the planetary surface, however, can linger long enough to present such a distinctive tail." Shporer explains that the planet is likely falling apart due to its low mass. "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," Shporer stated. "It's a runaway process, and it's only getting worse and worse for the planet." The team plans to carry out follow up observations this summer using the JWST. "This will be a unique opportunity to directly measure the interior composition of a rocky planet, which may tell us a lot about the diversity and potential habitability of terrestrial planets outside our solar system," Hon said. And in the meantime, the researchers said they're looking for more examples in TESS data. "Sometimes with the food comes the appetite, and we are now trying to initiate the search for exactly these kinds of objects," Shporer said. "These are weird objects, and the shape of the signal changes over time, which is something that's difficult for us to find. But it's something we're actively working on."
