Astronomers Spot Strange Exoplanet With A Tail

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Astronomers using the W. M. Keck Observatory in Hawaii have made a startling finding: a distant exoplanet with a tail hundreds of thousands of miles long. Planet WASP-69 b is located 164 light-years away, and as it orbit, it is followed by a stream of escaping gas that forms a tail ⁘ making it look a little like a comet.

The planet is a type called a hot Jupiter , meaning it is a large gas giant that orbits very close to its star. So close, in fact, that a year there lasts less than four days and it has a blistering temperature of over 600 degrees Celsius.

This close proximity to the star also causes its most distinctive feature, the tail. Radiation from the star bombards the atmosphere of the planet, stripping away gases like hydrogen and helium. And as streams of particles from the star called stellar winds hit the planet, they pull these escaping gases into a tail shape. The tail has been observed to be more than 7.5 times the radius of the planet, meaning that it stretches for over 350,000 miles.

But it could be even longer as the researchers didn⁘t have enough telescope time to observe the full length of the tail. However, because it is formed by stellar winds, the tail could also shrink over time if the wind lessens.