The planet spiraling into the star can provide a glimpse into the end of the Earth

An alien planet found spiraling towards its doom around an aging star

An artist’s concept of the Kepler-1658 system. Kepler-1658b, which orbited with a period of just 3.8 days, was the first exoplanet candidate discovered by Kepler. Credit: Gabriel Perez Diaz/Instituto de Astrofísica de Canarias

For the first time, astronomers have identified a planet spiraling toward a catastrophic collision with its aging sun, potentially providing a glimpse into how Earth may one day end.

In a new study published on Monday, a team of mostly US-based scientists said they hope the doomed exoplanet Kepler-1658b can help shed light on how worlds die as their stars age.

Kepler-1658b, which is 2,600 light-years from Earth, is known as a “hot Jupiter” planet.

While similar in size to Jupiter, the planet orbits its host star one-eighth the distance between our sun and Mercury, making it far hotter than the gas giant in our own solar system.

Kepler-1658b’s orbit around its host star takes less than three days — and it’s getting shorter by about 131 milliseconds a year, according to the study published in The Astrophysical Journal Letters.

“If it continues to spiral toward the star at the observed rate, the planet will collide with the star in less than three million years,” said Shreyas Vissapragada, a postdoctoral fellow at the Harvard–Smithsonian Center for Astrophysics and the study’s lead author.

“This is the first time we have observed direct evidence of a planet spiraling towards its evolved star,” he told AFP.

An evolved star has entered the “subgiant” phase of the star’s life cycle, when it begins to expand and brighten.

Kepler-1658b’s orbit is shortened by the tides, in a similar process to how Earth’s oceans rise and fall each day.

This gravitational push-and-pull can work both ways—for example, the Moon is very slowly spiraling away from Earth.

Earth’s ‘ultimate adios’?

So could Earth be headed for a similar doom?

“Death-to-star is a fate that awaits many worlds and could be Earth’s ultimate adios billions of years from now as our Sun ages,” the Center for Astrophysics said in a statement.

Vissapragada said that “in five billion years or so the Sun will evolve into a red giant star”.

While the tidally driven processes seen on Kepler-1658b “will drive the decay of Earth’s orbit toward the Sun,” this effect could be counteracted by the Sun losing mass, he said.

“Earth’s ultimate fate is somewhat unclear,” he added.

Kepler-1658b was the first exoplanet ever observed by the Kepler space telescope, which was launched in 2009. However, it took nearly a decade of work before the planet’s existence was confirmed in 2019, the Center for Astrophysics said.

Over the course of 13 years, astronomers were able to observe the slow but steady change in the planet’s orbit as it crossed the face of its host star.

A “big surprise” was that the planet itself is quite bright, Vissapragada said.

Previously, it had been thought that this was because it is a particularly reflective planet, he said.

But now scientists believe that the planet itself is far hotter than expected, possibly due to the same forces driving it towards the star.

More information:
The possible tidal death of Kepler’s first planetary system, The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/aca47e

© 2022 AFP

Citation: Planet spiraling into star may offer glimpse into end of Earth (2022, December 24) Retrieved December 24, 2022, from earth.html

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