Enormous 'hot Jupiter' exoplanet has 18 hour orbit of its star

Jupiter sized exoplanet with a surface temperature of 1,800F ‘is on the edge of destruction’ as it orbits around its star once every 18 HOURS

  • The discovered planet – called NGTS-10b – is 20 per cent larger than Jupiter 
  • The gas giant has a surface temperature of about 1,800 degrees Fahrenheit 
  • The star is about 70 per cent as large as our Sun with a cooler temperature  

An exoplanet dubbed NGTS-10b is on a death spiral towards its own star due to its close orbit – just once every 18 hours, leading to a surface temperature of 1,800F.

The gas giant is speeding around a star similar to the Sun but about 70 per cent smaller and cooler than our star – it’s about 1,000 light years away.

Astronomers from the University of Warwick say it’s 18 hour orbit is the shortest time a planet of this type has been seen going around a star.

The destruction of the planet – about 20 per cent larger than Jupiter – may be visible from Earth in the next decade as tidal forces rip it apart, the team said. 

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This artist impression of a hot Jupiter orbiting close to a star shows just how dangerous its position is within its system – it could be ripped apart by tidal forces within a decade

The tidally locked planet is 27 times closer to its star than Mercury is to the Sun in our own solar system and may be a ‘death spiral’ hurtling towards its destruction. I

NGTS-10b was discovered as part of the Next-Generation Transit Survey (NGTS) – that’s where the NGTS part of its name comes from.

The exoplanet survey, based in Chile, aims to discover planets down to the size of Neptune using the transit method.

This method involves looking for a telltale ‘blip’ in the images of the star taken over a period of time – pointing to a planet passing in front of it.

At any one time the survey observes around 100,000 stars covering a 100 square degrees of sky visible from Earth.

WHAT IS THE PLANET NGTS-10b AND WHAT ARE ITS FEATURES? 

Planet NGTS-10b was discovered by astronomers using the Next-Generation Transit Survey.

  • It has a surface temperature of about 1,800 degrees Fahrenheit
  • It is tidally locked to its parent star – which is very similar to the Sun 
  • It orbits the star once every 18 hours – less than a day on Earth
  • It is 27 times closer to its star than Mercury is to the Sun  
  • It is about 1,000 light years away from the Earth
  • The planet is about 20 per cent larger than Jupiter 

The star reported in the Monthly Notices of the Royal Astronomical Society caught the eye of astronomers due to frequent dips in its light.

They found this was caused by the planet’s rapid orbit.

Lead author Dr James McCormac, from the university’s department of physics, said they were very excited by the discovery.

‘We are pleased that NGTS continues to push the boundaries in ground-based transiting exoplanet science through the discovery of rare classes of exoplanets.

‘Although in theory hot Jupiters with short orbital periods (less than 24 hours) are the easiest to detect due to their large size and frequent transits, they have proven to be extremely rare,’ the researcher said.

‘Of the hundreds of hot Jupiters currently known, there are only seven that have an orbital period of less than one day.’

Larger gas giant exoplanets with a similar size to the largest object after the Sun in our solar system are called Jupiter-type, if they are very close to their star they are called hot Jupiters

Researchers say the exoplanet orbits is so close to its star that eventually it would be ripped apart by the tidal forces from the larger body.

Co-author Dr David Brown said the ultra-short planets migrate in from the outer reaches of the solar system and are eventually consumed by the star.

This may happen fairly soon, according to Dr Daniel Bayliss, from the Warwick team. He said it could fall into its star at some point over the next decade.

NGTS is situated at the European Southern Observatory’s Paranal Observatory in the heart of the Atacama Desert in Chile.

The research into the rapidly orbiting exoplanet was presented in the Monthly Notices of the Royal Astronomical Society. 

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 

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