Scientists Discover the First Planet With a Tail

Illustration for article titled Scientists Discover the First Planet With a Tail

Scientists have discovered the first cometary planet, one with a huge tail, a stream of gas being ripped off by solar winds at 22,000 miles per hour. This jovian world is located 153 light-years from Earth.

The planet—called HD 209458b—orbits 100 times closer to its home star than our Jovian neighbor, traveling in an astonishingly fast 3.5-day orbit. For comparison, Mercury—our solar system fastest planet—has an 88-day orbit.

Since HD 209458b is so close to the sun, the stellar winds are ripping the planet's atmosphere apart. Scientists have used the Hubble's Cosmic Origins Spectrograph to gather evidence that support the theory that its 2,000ºF atmosphere is being ejected from its body at 22,000 miles per hour.


According to astronomer Jeffrey Linsky, of the University of Colorado in Boulder:

Since 2003 scientists have theorized the lost mass is being pushed back into a tail, and they have even calculated what it looks like. We think we have the best observational evidence to support that theory. We have measured gas coming off the planet at specific speeds, some coming toward Earth. The most likely interpretation is that we have measured the velocity of material in a tail [...] This large gas flow is likely gas swept up by the stellar wind to form the comet-like tail trailing the planet.

I don't know about you, but I'm happy that there are so many new things to watch and discover out there. [NASA]

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I'm no astrophysicist, but wouldn't this decrease the mass of the planet over time, thusly decreasing the force of gravity between the star an it's planet, pushing it back out into a larger orbit?