Scorching Hot Exoplanet Contains Unusual Amount of Nickel, Could Have Swallowed a Smaller Neighboring Planet

Around 634 light years away from the Earth, a cannibal exoplanet lurks with a seemingly dark history. Scientists explore its properties which led them to make conclusions about its past.

The Strangeness of the Distant Exoplanet

The giant planet WASP-76b is one of the most bizarre places in the universe. Its scorching atmosphere is full of vaporized metal and pours down iron on its night side.

WASP-76b orbits a star in the Pisces constellation, which is only slightly larger than our own Sun. Aside from this, its distance to its star is 12 times closer to Mercury's distance to the Sun. Further analysis reveals that the exoplanet is as hot as the surface of a small star, reaching up to 4,000 degrees Fahrenheit. Because of this, it can vaporize metallic elements such as nickel, iron, and magnesium. These are the elements that normally form rocks on Earth.

This property of WASP-76b benefits the astronomers at the University of Montreal, led by Stefan Pelletier. This is because the upper atmosphere of the exoplanet made of clouds of metal gas is easier to observe with telescopes such as the MAROON-X instrument on the Gemini North Observatory. Gas giants with cooler temperatures, like Jupiter and Saturn, are hard to follow and study because heavy elements like magnesium and iron are settling into the planet's deeper layer. Because of this, scientists are still unable to identify the amount of heavy metals hiding in the interior of Jupiter.

Devourer of a Neighboring Planet

Upon measuring the amount of light spectrum from WASP-76b, Pelletier and his team, determined the amounts of 11 chemical elements in the gas giant's upper atmosphere. The relative amounts of those metals give the researchers an idea of the material that originally formed the planet. Aside from the 11 chemical elements previously discovered in the gas giant, there are also rock-forming elements whose abundances cannot be determined for similar planets in our Solar System.

In the case of WASP-76b, its chemical composition is almost identical to its host star and our own Sun. From this information, astronomers concluded that it was created from the same cluster of gas and dust as its star.

Aside from this, another discovery was made by Pelletier and his team. The abundance of chemicals are helpful tracer in understanding the formation and evolution of a planet, but the investigation made on WASP-76b reveals some anomalies.

More nickel was found floating around the atmosphere of WASP-76b than there should be. The extra nickel is speculated to be the inner layers of a rocky little planet similar to Mercury. The deviation of abundance values from what is expected has led scientists to conclude that it might have swallowed a smaller planet. The astronomers suggest that in the past history of the star system, an unlucky planet might have passed too close to it, and the larger gas planet pulled it with its immense gravity.