The heavy metal planet being ripped apart by its own star

In a star system 900 light-years away, a planet roughly the size of Jupiter is leaching heavy metal gases into the atmosphere as the gravity of its nearby host star tugs it out of shape.

As a result, scientists say the unusual world is shaped like a football.

While planets of this size aren’t typically known to release heavy metals, as they tend to be cool enough for these to condense into clouds, the planet dubbed WASP-121b sits ‘dangerously close’ to its star, heating it up enough for them to escape as gases.

Researchers say the planet’s shape resembles that of a football due to its proximity to the host star. It sits so close that it is ‘on the cusp of being ripped apart’ by gravitational forces, according to NASA. Artist’s impression pictured 

‘Heavy metals have been seen in other hot Jupiters before, but only in the lower atmosphere,’ says David Sing of the Johns Hopkins University in Baltimore.

‘So you don’t know if they are escaping or not. With WASP-121b, we see magnesium and iron gas so far away from the planet that they’re not gravitationally bound.’

In a new study published to The Astronomical Journal, researchers analyzed observations from the Hubble Space Telescope and found that ultraviolet light from its close by host star is likely helping magnesium and iron make its way out of the upper atmosphere.

That, in turn, could make conditions even hotter.

‘These metals will make the atmosphere more opaque in the ultraviolet, which could be contributing to the heating of the upper atmosphere,’ Sing said.

WASP-121b is an oddball not just for its escaping metals, but for its shape, too.

Researchers say the planet’s shape resembles that of a football due to its proximity to the host star.

It sits so close that it is ‘on the cusp of being ripped apart’ by gravitational forces, according to NASA.

‘We picked this planet because it is so extreme,’ Sing said. ‘We thought we had a chance of seeing heavier elements escaping.’

The observations suggest the upper atmosphere reaches temperatures upwards of 4,600 degrees Fahrenheit.

This scorching environment combined with other characteristics make it a good place to search for elements such as magnesium and iron.

In a new study published to The Astronomical Journal, researchers analyzed observations from the Hubble Space Telescope and found that ultraviolet light from its close by host star is likely helping magnesium and iron make its way out of the upper atmosphere. File photo

‘It was a surprise, though, to see it so clearly in the data and at such great altitudes so far away from the planet,’ the researcher said.

‘The heavy metals are escaping partly because the planet is so big and puffy that its gravity is relatively weak.

‘This is a planet being actively stripped of its atmosphere.’

These conditions also make it a prime target for the upcoming James Webb Space Telescope, according to NASA.

Its atmosphere could also be home to water and carbon dioxide, which would appear at longer wavelengths.

Studying WASP-121b could also teach us about the ways in which planets lose their primordial atmospheres.

‘The hot Jupiters are mostly made of hydrogen, and Hubble is very sensitive to hydrogen, so we know these planets can lose the gas relatively easily,’ Sing said.

‘But in the case of WASP-121b, the hydrogen and helium gas is outflowing, almost like a river, and is dragging these metals with them. 

‘It’s a very efficient mechanism for mass loss.’

HOW DO SCIENTISTS STUDY THE ATMOSPHERE OF EXOPLANETS?

Distant stars and their orbiting planets often have conditions unlike anything we see in our atmosphere. 

To understand these new world’s, and what they are made of, scientists need to be able to detect what their atmospheres consist of.  

They often do this by using a telescope similar to Nasa’s Hubble Telescope.

These enormous satellites scan the sky and lock on to exoplanets that Nasa think may be of interest. 

Here, the sensors on board perform different forms of analysis. 

One of the most important and useful is called absorption spectroscopy. 

This form of analysis measures the light that is coming out of a planet’s atmosphere. 

Every gas absorbs a slightly different wavelength of light, and when this happens a black line appears on a complete spectrum. 

These lines correspond to a very specific molecule, which indicates it’s presence on the planet. 

They are often called Fraunhofer lines after the German astronomer and physicist that first discovered them in 1814.

By combining all the different wavelengths of lights, scientists can determine all the chemicals that make up the atmosphere of a planet. 

The key is that what is missing, provides the clues to find out what is present.  

It is vitally important that this is done by space telescopes, as the atmosphere of Earth would then interfere. 

Absorption from chemicals in our atmosphere would skew the sample, which is why it is important to study the light before it has had chance to reach Earth. 

This is often used to look for helium, sodium and even oxygen in alien atmospheres.  

This diagram shows how light passing from a star and through the atmosphere of an exoplanet produces Fraunhofer lines indicating the presence of key compounds such as sodium or helium