Погляд художника на кометний хвіст планети, яка розпадається під час оберту навколо материнської зірки. Джерело: NASA
Astronomers have observed for the first time how two worlds outside the solar system eject their outer layers into space — and this data, collected James Webb Space Telescope (JWST)offer an «unprecedented» view of what distant planets hide in their insides (in fact, something that is beyond the reach of even the Earth).
The first exoplanet, K2-22b —, is a rocky world the size of Neptune that is so close to its star that it takes only 9 hours to reach it. According to astronomers, the heat of this «Sun» actually fries the planet and provides a temperature of 1826°C — which is enough to melt the rock and even vaporize it. Recent JWST observations have shown that the vaporized planet had a shape with an extended tail that resembled a comet.
«This is an amazing and serendipitous opportunity to understand the inner workings of the Earth’s planets,» says study co-author Jason Wright, a professor of astronomy and astrophysics at the University of Pennsylvania.
Another distant and «toasted» world is the exoplanet BD+054868Ab, which was first discovered by the Transiting Exoplanet Survey Satellite (TESS) space telescope. Today, it is the closest exoplanet to Earth that has evaporated and has two massive tails that together extend for 9 million km.
«These planets are literally spewing out their insides,» said Nick Tusay, a graduate student in the Penn State Department of Astronomy and Astrophysics who led the study. «Thanks to JWST, we finally have the means to study their composition and determine what planets orbiting other stars are really made of».
Articles detailing the findings on both exoplanets were loaded as preprints and are still being reviewed.
The planets were found after TESS and JWST observed thousands of stars in search of periodic dips in light that occur when a planet crosses its star. These traces, known as transits, contain spectral fingerprints of the planets’ chemical composition that allow astronomers to construct what their insides once looked like.
For example, in studying K2-22b, JWST detected carbon dioxide and nitric oxide, which is unusual because these gases are usually associated with icy bodies. Tusai and his colleague speculate that the planet may have originally formed farther away from its star and migrated closer due to gravitational perturbations. In the meantime, BD+054868Ab is losing so much material that it could cease to exist in about 1-2 million years — a blink in the typical lifespan of planets in less extreme environments that exist for billions of years.
«The rate at which the planet is evaporating is catastrophic, and we are incredibly lucky to be witnessing their last hours,» concludes Mark Hong, a postdoctoral fellow at MIT who led the discovery of BD+054868Ab.
Source: livescience