Scientists have been baffled to discover a ‘clingy’ planet that is ensuring its own doom.
The first ever recorded ‘planet with a death wish’ orbits so close to its host star that it triggers huge flares of radiation every time it orbits.
Those flares are up to 10,000 times more powerful than those produced by our sun, and each one blasts away a little more of the planet’s wispy atmosphere.
Over the next 100 million years, scientists predict the planet will shrink from an almost Jupiter-sized giant to a planet the size of Neptune, around a third of its original size.
The star, named HIP 67522, is located about 415 light years from Earth and is a little cooler and larger than the sun.
However, unlike our sun, which is middle-aged at 4.5 billion years old, HIP 67522 is extremely young at only 17 million years old.
Scientists believe that young stars like this spin rapidly and churn up powerful magnetic fields.
When a planet passes close by, it can interact with these fields and charge up vast quantities of power, which is eventually released as devastating solar flares.
Scientists have been baffled to discover a ‘clingy’ exoplanet that is ensuring its own doom by orbiting too close to its host star (artist’s impression)
Since the 1990s, scientists have hypothesised that a combination of a young star and a close orbiting planet might produce powerful flares of radiation.
However, it is only now that the most advanced telescopes are capable of spotting these distant events.
After scanning a selection of potential stars using NASA’s Transiting Exoplanet Survey Satellite, the researchers realised that HIP 67522 was worth investigating further.
Thanks to previously gathered data, scientists knew that the closest planet to this star, creatively dubbed HIP 67522 b, takes just seven days to make a complete orbit.
This meant that the planet must be extremely close to its host star, making it an ideal candidate for flare hunting.
After securing a window to use the European Space Agency’s powerful Characterising Exoplanet Satellite, known as Cheops, they started watching for solar flares.
Soon, the researchers had spotted 15 solar flares, almost all coming in our direction as the planet passed between its star and Earth.
Since these flares only occurred when the planet passed in front of its star, they are very likely triggered by the planet.
The star’s closest planet orbits in just seven days, so close that it whips up the magnetic fields to produce solar flares up to 10,000 times stronger than those produced by our sun (artist’s impression)
However, exactly how this process takes place is still something of a mystery.
Lead author Dr Ekaterina Ilin, of the Netherlands Institute for Radio Astronomy, told MailOnline: ‘We don’t know for sure. But we have an idea of how it could work.
‘The planet couples into the star’s magnetic field and sets off waves that travel along the field line to the star.
‘Once arrived in the star’s atmosphere, the wave’s energy destabilises coronal field loops that then erupt as flares.’
You can imagine this like the planet shaking the star’s magnetic field lines like massive ropes, sending waves racing down them.
When those waves meet the end of the field line at the star’s surface, it triggers a flare.
Even though researchers had long predicted this might be possible, these flares were around 100 times more energetic than anyone had expected.
Since the explosions are so much more powerful than the waves that create them, the researchers believe the planet might be setting off explosions that were already waiting to happen.
This star has magnetic fields even more powerful than those of our own sun. As the planet orbits, it shakes up these fields and sends waves of energy down to the solar surface. Once the waves hit the end of the field line, they produce devastating solar flares (stock image)
Scientists believe that this process will eventually shrink the planet’s atmosphere until it has diminished from the size of Jupiter to the size of Neptune
This is bad news for HIP 67522 b, which is one of the wispiest exoplanets ever discovered and has the density of candy floss.
These flares mean the planet is exposed to six times as much high-energy radiation as it would otherwise be.
Dr Ilin says that this probably won’t totally destroy the planet; it will eventually be stripped of its atmosphere and become much smaller over the next 500 million years.
Dr Ilin says: ‘So far, we have found one. But if the youth of the star-planet system is the reason for the observation, it is possible that this is a quite common occurrence.’
While the researchers have only detected a ‘handful’ of planet-star pairings that could produce flares, more observations may soon reveal more of these destructive interactions.
Going forward, Dr Ilin says the next step will be to make follow-up observations in different wavelengths of light to see what kind of radiation is being released.
If a lot of the flares’ energy is in the form of high-frequency ultraviolet or X-ray radiation, that would be especially damaging for the planet.
In the future, the European Space Agency will use its planned exoplanet hunter, Plato, to look for sun-like stars, which could be producing smaller flares that aren’t visible to other telescopes.
Scientists study the atmosphere of distant exoplanets using enormous space satellites like Hubble
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
