Heat stroke coming for Kepler-1658b… Astronomers have spotted a distant planet dangerously close to its aging star for the first time, according to a study released on Monday that gives possible insight into how Earth could end up.
Located 2,600 light-years from Earth, Kepler-1658b is a exoplanet – that is, a planet outside the solar system – about as big as Jupiter. But unlike this gas giant far from the Sun, Kepler-1658b orbits its star only one-eighth the distance that separates our star from Mercury, the planet closest to it.
Collision in less than three million years
This “hot Jupiter” goes around its star in less than three days, and this period of revolution is shortened by about 131 milliseconds per year, describes a study published in The Astrophysical Journal Letters.
“At this rate, the planet will collide with its star in less than three million years”, analyzes Shreyas Vissapragada, of the Harvard Center for Astrophysics – Smithsonian, main author of the study.
“This is the first time that we have observed direct evidence of a planet with a spiral trajectory around its aging star”, explains the astrophysicist to AFP. The star in question is at an advanced stage in its cycle, when it begins to swell and become brighter and brighter.
The orbit of Kepler-1658b inexorably decreases under the effect of the gravity exerted by the star, similar to that exerted by the Moon on various points on Earth. This effect called tidal force can attract two bodies just as well as it can move them away from each other – the Moon for example moves away very slowly from the Earth with a spiral trajectory.
Same inevitable end for the Earth?
Will our planet experience the same process of disintegration? “A star-induced death of a planet is a fate that awaits many worlds and could be Earth’s ultimate farewell billions of years from now as our Sun evolves,” writes the Astrophysics Center. in a press release.
In about 5 billion years, the Sun will become a “red giant” which will grow bigger and bigger, in the same line as the host star of Kepler-1658b.
Like the exoplanet, the Earth could move inexorably closer to the Sun under the effect of tidal forces. But this effect could also be counterbalanced by the loss of mass from the Sun, specifies Shreyas Vissapragadan, stressing that “the ultimate fate of the Earth remains unclear”.
Kepler-1658b has been intriguing for thirteen years
Kepler-1658b was the first exoplanet observed with the Kepler space telescope, in 2009. For 13 years, scientists had observed the slow but steady change in the planet’s orbit passing in front of its host star.
Finding it surprisingly bright compared to other exoplanets, they have long assumed that it reflects starlight particularly well. They now believe that Kepler-1658b is even hotter than expected due to the attraction exerted by the star.