In a finding that redefines the understanding of exoplanets, a team of scientists led by Dakotah Tyler of the University of California, Los Angelesdiscovered that the exoplanet WASP-69b It’s not just a giant gaseous sphere similar to Jupiter, sino a celestial body that leaves a trail of gas in its pathresembling a comet. According to NASA, this unusual feature was detected through detailed observations made with the Keck II telescope, using the NIRSPEC spectrograph.
The discovery raises a new perspective on how atmospheres planetary They can interact with the stellar environment. While some exoplanets lose gases uniformly, WASP-69b projects a hydrogen and helium tail which extends more than 563,269 km. (at least 7.5 times the planet’s radius), a phenomenon driven by the intense stellar winds of its host star.
According to Tyler, this behavior is comparable to what happens with a windsock which inflates when receiving a current of air. “If the stellar winds intensify, the gas escapes from the planet and is molded into a tail”explained the main researcher. This makes WASP-69b a natural laboratory for understanding how exoplanets lose mass and how these losses are shaped by their cosmic environment.
WASP-69band “Hot Jupiter”is a gas giant that orbits at a short distance from its star, a K-type dwarf. Due to this proximity, intense stellar radiation heats its outer layers, causing a phenomenon called photoevaporationin which light gases such as hydrogen and helium are launched into space.
However, instead of escaping in all directions, the stellar winds of the host star redirect this flow of gas, sculpting a long tail similar to that of a comet. This dynamic interaction reveals how extreme stellar environments can alter planetary evolution.
Scientists estimate that WASP-69b loses about 200,000 tons of gas per seconda pace that, while impressive, does not threaten its immediate existence. In the long term, it is estimated that in the 7 billion years of life in its system, the planet has lost a mass equivalent to seven times that of Earth.
The shape and length of WASP-69b’s tail are not fixed. He stellar wind It acts as a cosmic sculptor, varying the tail depending on its intensity and the activity of the star. “If the stellar wind weakens, the planet’s atmosphere would still escape, but more symmetrically and without forming a tail,” Tyler commented.
The researchers believe that this variable interaction could also help study stellar activity in other stars. The planetary tails They could act as “stellar wind indicators,” providing clues to stellar phenomena that would otherwise be difficult to observe.
This discovery is detailed in the scientific article published in The Astrophysical Journaltitled “The WASP-69b exhaust envelope is confined to a tail that extends at least 7 Rp.”with observations made in 2019 and analysis updated until 2024.
Future studies could offer a more complete understanding of how these exoplanets lose their atmospheres and how star forces They shape their environments. The investigation of WASP-69b opens a new window to explore the effects of stellar radiation on exoplanets, revealing a universe where planets are not only passive spheres, but dynamic celestial bodies, in constant transformation.
With each new observation, astronomers hope to answer fundamental questions about planetary evolutionthe behavior of the atmospheres and the complex relationship between stars and planets in distant systems. WASP-69b, the “planet with a tail,” has gone from being just another exoplanet to becoming a symbol of the extraordinary diversity of the cosmos.
