For the first time, astronomers have found a planet that is spiralling towards a catastrophic collision with its aging sun, possibly offering a glimpse into how Earth might end in the future.
According to a team of scientists with the majority of their bases in the US who published a newspaper on the subject on Monday, the unhappy exoplanet Kepler-1658b may offer insight into how planets degrade as their sun ages. Kepler-1658b is a “hot Jupiter” that is 2,600 light years from Earth.
Despite being similar in size to Jupiter and orbiting its star at a distance one eighth that of our Sun and Mercury, the planet is hotter than the gas giant in our own solar system.
According to a study published in The Astrophysical Journal Letters, Kepler-1658b’s Orbit around its host star lasts less than three days and is shrinking by about 131 milliseconds annually.
Shreyas Vissapragada, a postdoc at the Harvard-Smithsonian Center for Astrophysics and the study’s principal author, said that if the planet spirals towards its star at the observed rate, it will crash with its star in less than three million years.
He told AFP, “This is the first time we’ve seen clear evidence of a planet spiralling into its evolved star.
Shortening Of Kepler-1658b’s Orbit
Having reached the “subgiant” stage of the stellar life cycle, an evolved star has begun to grow and become brighter. The tides, which cause the Earth’s seas to rise and fall each day, are shortening Kepler-1658b’s orbit.
The Moon is gently spiralling away from Earth as an illustration of how gravitational push-pull may go both ways.
Earth’s Ideal Farewell
Could Earth be headed for a similar fate then?
The Center for Astrophysics said in a statement that as our Sun ages, “death-by-star is a fate assumed to await many worlds and could be the Earth’s Ideal Farewell in billions of years.”
The Sun “will grow into a red giant star in about five billion years,” according to Vissapragada. The tidally-driven processes observed on Kepler-1658b “will drive the degradation of the Earth’s orbit towards the Sun,” he said, but that effect might be offset by the Sun shedding mass.
The Planet’s Extant
He continued, “It’s not entirely apparent what the Earth’s future holds.” The 2009-launched Kepler space telescope’s first exoplanet to be spotted was Kepler-1658b.
The planet’s existence was finally verified in 2019 after nearly ten years of research, according to the Center for Astrophysics.
Astronomers have been able to track the planet’s modest but constant orbital movement as it passes in front of its home star over a period of 13 years. The fact that the planet itself is quite bright was one “huge surprise,” according to Vissapragada.
Previously, he added, it had been assumed that this was due to the planet’s very high reflectivity. According to the researchers, the planet may be far hotter than initially thought because of the same factors that are pushing it into its star.