In a land far, far away from here (330 light years from Earth), in the Phoenix constellation, lies an exoplanet (a planet orbiting a star other than the Sun) named WASP-18b. This planet is unlike any other planet that we have yet discovered, one on which a year is the same length as a day on Earth.
Wouldn’t it be fun to live on a planet where you could celebrate your birthday every day? However, as expected, this planet can’t be inhabited by humans. It’s actually good thing that humans can’t reach this planet, as mankind would never be able to survive the harsh conditions of the planet. More importantly, though, the planet itself is doomed. It will inevitably be destroyed by its parent star, WASP-18, which is roughly the size of our Sun.
Let’s look at why a planet 10 times the size of Jupiter is headed for imminent destruction.
The story of WASP-18 and WASP-18b
Wasp-18b: “Hot Jupiter”
WASP-18b is affectionately called “Hot Jupiter“. Hot Jupiter belongs to a class of exoplanets that have characteristics similar to that of Jupiter, but have a higher surface temperature, as they orbit very close to their parent star. For example, Jupiter orbits its parent star (the Sun) at 5.2 astronomical units. In comparison, WASP-18b orbits its parent star (WASP-18) at 0.01 astronomical units (3.1 million kilometers). Yes, if you were curious, it’s going to be hot as hell.
WASP-18b is so close to its parent star that it orbits around the star in just 23 hours. In comparison, Jupiter takes about 12 years to orbit the Sun. Being so close to its parent star is not good news for “Hot Jupiter” and its parent star. Observations made by NASA’s Chandra X-ray Observatory has shown that WASP-18 is aging its parent star much faster than it should (the story of every teenager and their parents). This is the first planet known to have caused its star to display older traits than it should.
No Planet for Old Stars
The planet being so close to its star may cause a dampening of the star’s magnetic fields. Astronomers have determined the age of WASP-18 to be between 500 million and 2 billion years old, which is relatively young for a star. Younger stars are more active, they exhibit stronger magnetic fields, and display more X-ray emissions and larger flares as compared to older stars. As stars get older, their X-ray and magnetic activities decrease.
Astonishingly, this extensive observation made by the Chandra X-ray observatory reveals no X-ray emissions from WASP-18. Research has shown that WASP-18 is 100 times less active than it should be for its age. The strong gravitational pull of WASP-18 is responsible for disrupting the star’s magnetic field, which is similar to the effect that the moon has on Earth’s tides, but on a much larger scale.
An Unstoppable Force Meets an Immovable Object
Although it is the star getting old because of its planet, the life of the planet is actually in danger, due to its closeness to the star. The planet, which orbits the star in an astonishing speed of only 23 hours, will eventually spiral into its parent star in about a million years (a small duration on the cosmic scale). The collision with its star will eventually lead to the destruction of the planet WASP-18b, which is how this tragic father-son story will end.