The planet WASP-69 b has recently been highlighted thanks to a surprising discovery: it has a “queue” gas, leaving behind an atmospheric trail. This unique characteristic reveals that the planet gradually loses its atmosphere, composed of light particles of hydrogen and helium which escape from the external atmosphere.
Tail formation mechanisms
THE “Hot Jupiters” Like Wasp-69 B, gigantic sparkling planets very close to their star, undergo a phenomenon called photoévaporation. When the stellar radiation heats the external atmosphere of these planets, the light gases are heated and powered in space. The Wasp-69 B star thus erodes the atmosphere of the planet over time.
The stellar winda continuous flow of charged particles emitted by the external atmosphere of the star, plays a key role in the configuration of this gas leak by forming an exoplanetary tail. This stellar wind therefore shapes the gas which escapes into a tail which unfolds on the back of the planet.
Impact of the stellar wind on the tail
The size and shape of the tail can vary depending on the intensity of the stellar wind. As Dakotah Tyler explains, astrophysicist at the University of California in Los Angeles and the main author of the study, If the stellar wind decreasesthe atmosphere that escapes may not form a tail, remaining spherical and symmetrical. Conversely, a stronger stellar wind would sculpt this atmosphere in a more structured tail, similar to a “Air handle”.
Hera is soon on the way to study the asteroid deviated in 2022 by the NASA Dart mission
Observations and discoveries
The research team observed that the WasP-69 B tail extended to more than 7.5 times the radius of the planetor more than 350 000 miles. This measure is however considered as an lower limit, the observations having been interrupted before the complete disappearance of the tail signal.
Consequences of gas loss
Despite the significant loss of gas – approximately 200,000 tonnes per second -WASP-69 B loses its atmosphere at a very slow pace. Estimably, every billion years, it loses a mass of gas equivalent to that of the earth. Since its solar system is about 7 billion years, the planet has already lost the equivalent of seven gas lands.
Discovery of an immense underground ocean containing 3 times more water than all the oceans combined
Scientific relevance of discovery
This study offers precious insights on interactions between planetary and stellar atmospheres, as well as on the behavior of stellar winds. THE exoplanetary tailsinfluenced by stellar activity, could also serve as indicators of the behavior of the stars over time.
Published in “The Astrophysical Journal” in January 2024, this research led by Dakotah Tyler and carried out with the help of the Nirspec spectrograph of Keck/Nirspec, opens up new ways to understand the complex dynamics of planetary and stellar systems, thus enriching our knowledge of the universe.
Related News :