Exoplanet WASP-12 in Its Death Throes

Among the more than 400 exoplanets discovered thus far, the one known as WASP-12 is fairly important. Astronomers say that it is the only known planet orbiting a star outside our solar system that revolves around a yellow dwarf. The entire system, featuring the star WASP-12 and its planet, is located about 867 light-years away from Earth. Unlike our home world, which takes about 365 days to complete a full circle around the Sun, WASP-12b is so close to its parent star that it basically completes a single rotation in 26 hours – the length of its year.

This proximity between the two celestial bodies is causing massive devastation on the planet, which will most likely in the near future get disintegrated. It is a gas giant-class planets, about 1.4 times more massive than Jupiter, but with a diameter about 3.6 times larger than that of our neighboring planet. Because the surface of its star is so close to its own, the exoplanet is constantly experiencing temperatures that reach as high as 2,200 degrees Celsius, or roughly 4,000 degrees Fahrenheit. But the thing that amazes experts most is the fact that its body is so inflated. This is unnatural by cosmic laws, and a similar instance has not been encountered before.

At first, scientists thought that the massive heat levels the parent star produced were directly responsible for this phenomenon, but new data seems to indicate that other factors may be at play too. Chinese scientists from the Peking University in Beijing, led by astrophysicist Shu-lin Li, say that the gravity the star exerts apparently plays a very large part of how WASP-12b is deformed. The two bodies are tidally-locked, which means that the exoplanet always keeps the same face oriented towards its parent star. The same is true in the case of the Earth-Moon system, which is also tidally-locked.

“Whereas tidal force on the Earth leads to a few meter changes in the height of the ocean surface, that on WASP-12b is 10 million times larger,” the team leader says. He explains that the massive volume of inflation the planet experiences makes it lose a large portion of its atmosphere every year. Calculations place these quantities about 1/1000th of the Moon's mass. “We are witnessing the ongoing disruption and death march of a planet,” Li says. He also reveals that future observations of the exoplanet may reveal a jet of gas flowing from the planet into the star, which could become detectable by using a number of telescopes, Space reports.

The team also believes that the WASP-12 system may have not yet revealed all of its secrets. Li argues that another exoplanet orbits around this star, influencing the path that WASP-12b takes. This other planet is believed to be a super-Earth, a smaller planet between 5 and 10 times the mass of our own planet. Details of the study were published in the February 25 issue of the esteemed publication Nature.