An alien planet not far from Earth, called WASP-69 b, has revealed an extraordinary feature: a massive tail of gas stretching over 350,000 miles.
This tail, longer than 40 Earths lined up in a row, is the result of gas escaping from the planet's atmosphere and being shaped by powerful winds from its star. Scientists say it resembles a gigantic "windsock" in space.
Stellar Winds Create Massive Gas Tail on Nearby Exoplanet WASP-69 b
WASP-69 b is a type of gas giant known as a "hot Jupiter." Similar in size to Jupiter but much lighter, this planet orbits extremely close to its host star, completing a full orbit in just 3.9 days.
Its proximity to the star causes its atmosphere to heat up, leading to a process called photoevaporation. In this process, lightweight gases like helium and hydrogen escape into space.
What makes WASP-69 b special is how these escaping gases are pushed into a tail by the star's "stellar wind."
According to LiveScience, stellar wind is a continuous stream of charged particles emitted by a star. For WASP-69 b, this wind shapes the escaping gases into a spectacular comet-like tail.
The formation of the tail depends on the strength of the stellar wind. If the wind weakens, the gas escapes evenly around the planet, creating a more symmetrical shape.
However, when the wind is strong, it pulls the gas into a long tail trailing behind the planet. Scientists compare this to how a windsock fills and flutters in a breeze.
The tail, which measures at least seven times the planet's radius, is visible when illuminated by the light of its star. This gives astronomers a unique opportunity to study the interactions between a planet's atmosphere and stellar wind.
WASP-69 b's Atmosphere Slowly Escaping into Space
WASP-69 b has been losing its atmosphere for billions of years. Each second, about 200,000 tons of gas escape the planet, equivalent to the weight of 1,600 blue whales, SciTechDaily said.
Over its 7-billion-year lifetime, the planet has likely lost an amount of gas equal to seven Earth masses. Despite this, there is no immediate danger of the planet losing all its atmosphere.
The discovery of WASP-69 b's tail provides important insights into how planets evolve. It also offers a rare method for studying stellar winds on distant stars, as the tail acts like a "windsock," revealing the wind's strength and direction.
This research could help scientists understand more about exoplanets and the stars they orbit.
The findings were published in January 2024 by a team of researchers led by Dakotah Tyler, using data from Hawaii's W. M. Keck Observatory. This remarkable discovery showcases the incredible dynamics at play in distant solar systems.
