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An exoplanet very close to its star is provoking star eruptions and destroying itself. This is the first direct proof of magnetic interaction between a planet and its star.
According to, the astronomers who work with the Cheops Missionof the European Space Agency (ESA), they observed an exoplanet that seems to be unleashing potent radiation outbreaks from its host star.
These intense explosions are removing the fine atmosphere of the planet, gradually reducing its size every year.
This is the first direct evidence that a planet actively influences its star this way. Although scientists had already raised this hypothesis in the 1990s, the outbreaks observed in this study are about 100 times stronger than forecast.
Observations of telescopes, such as (NASA/ESA/CSA) and TESS (NASA transit exoplanet research satellite) had already provided some initial clues about this exoplanet and its star.
The star, called HIP 67522it is slightly larger and colder than our sun, but much younger – is only 17 million years oldcompared to the 4.5 billion of the sun. It has two known planets, the nearest – HIP 67522 b – Complete an orbit in just seven days.
Comparatively, our sun has a weaker and more stable magnetic field. Scientists already knew that stars with magnetic fields can generate eruptions when their field lines intertwine and break, freeing energy. These eruptions can manifest in the form of radio emissions, visible light or even gamma rays.
From a Discovery of the first exoplanet in the 1990sthat astronomers interrogate if some of them will not be enough close to their stars to disturb their magnetic fields. If so, they could be provoking these eruptions.
Given the youth of the hip 67522 star and its considerable size, the investigators anticipated that it was highly active, with rapid rotation and intense internal dynamics – characteristics that favor the generation of strong magnetic fields.
A team led by Ekaterina Ilfrom the Radio Astronomy Institute of the Netherlands, thought it was at the time of investigate this hypothesis with current space telescopes. The study was in Nature.
“We had never seen systems like Hip 67522, when the planet was discovered, was the youngest known to orbit your star in less than 10 days“, Explains Ekaterina.
The team used Tess to look for stars that could be emitting eruptions induced by nearby planets. When the Tess observed the Hip 67522 system, the team suspected that It was facing something special. To confirm, they resorted to Cheops – The ultra -need satellite of ESA.
“We quickly requested observation time with Cheops, which can point to specific stars with enormous accuracy,” says Ekaterina. “With Cheops, we detected more rashes – in all, 15 – almost all coinciding with the passage of the planet in front of the star, view of the earth.”
As we are observing these eruptions precisely when the planet drives in front of the star, it is very likely that they are caused by it.
Our own sun regularly frees gusts from energy – which manifest themselves as “Spatial Meteorology“It can cause auroras or damage technology. But to this day, we had only seen this energy flow in one direction: From the star to the planet.
Given the orbital radius so short of hip 67522 Bea strength of the star’s magnetic field, the team concluded that the planet is close enough to affect The magnetic behavior of the star.
The hypothesis is that the planet, when orbiting, accumulates energy and sends it back in the form of waves through the star’s magnetic field lines – as if we pulled and loose a rope. When these waves reach the star surface, release energy in the form of eruptions.
“The planet seems to be causing particularly energetic eruptions,” says Ekaterina. “The waves it sends through the magnetic lines firing eruptions at specific times. But the energy of eruptions is far higher than the waves. We think these waves are spoilting explosions that were about to happen.”
When Hip 67522 B was discovered, it was the youngest planet known to orbit so close to its star. Nonetheless, Other similar systems have already been identifiedand it is likely that there are dozens more in the near universe.
Ekaterina and your team are eager to study these unique systems With Tess, Cheops and other missions.
“I have a lot of questions, because this is a Fully New Phenomenon “There are still many details to clarify,” he says.
“There is two priorities: First, observe in other wavelengths (Cheops copper from visible to near infrared) to realize what type of energy is being released – for example, ultraviolet rays and x -rays are especially harmful to the planet.
Second, find and study other similar systems. If we can move from a single case to a group of 10 to 100, theorists will have much more to work. ”
Maximillian Günther, Scientist of the Cheops Mission at ESA, is also enthusiastic about the unexpected way the satellite has contributed to science. “Cheops was designed to measure the size and atmosphere of exoplanets, not to observe eruptions. It is wonderful to see the mission to overcome its own limits and to produce results beyond expected. ”
In the future, the New Plato Telescope from ESA will also study solar stars like Hip 67522. It will be capable of detecting much smaller eruptionsallowing us to better understand what is going on.
For the first time, we see a planet directly influenced its host star – contrary to the assumption that stars behave independently.
And not only the Hip 67522 B planet is provoking these eruptions-it is doing so in its own direction. As a result, receives six times more radiation than I would normally receive.
Being bombarded with such high energy radiation is not a good sign for hip 67522 b. The planet is similar to Jupiter in size, but has the density of cotton candy, being One of the lightest exoplanets ever discovered.
Over time, this radiation is corroding its light atmospherecausing the planet to lose mass much faster than expected. Over the next 100 million years, you could go from a planet almost the size of Jupiter to a smaller, similar to Neptune.
Teresa Oliveira Campos, Zap //
