‘Nearby’ Red Giant Star May Predict Earth’s Demise

This is a omposite view of L2 Puppis in visible light (from the VLT/SPHERE instrument, blue colors) and ALMA continuum (orange colors). The central star light has been subtracted from the ALMA image to better show the companion object. Credit: P. Kervella et al. (CNRS / U. de Chile / Observatoire de Paris / LESIA / ESO / ALMA)

(CN) – A nearby star could provide astronomers with a glimpse into Earth’s future, as the star’s evolution to a massive red giant star could show whether Earth will survive when the sun eventually grows to 100 times its current size.

Researchers studied L2 Puppis, a star in the constellation of Puppis that once resembled the sun. While its proximity to Earth – 208 light-years away, relatively close in astronomy terms – makes the star a candidate for further analysis, its evolutionary history could predict Earth’s death.

“The fate of the Earth is still uncertain. We already know that our sun will be bigger and brighter, so that it will probably destroy any form of life on our planet,” said co-author Leen Decin. “But will the Earth’s rocky core survive the red giant phase and continue orbiting the white dwarf?”

After growing to a red giant star, the sun will eventually lose a large portion of its mass due to very strong stellar winds and become a white dwarf – a small, dense star.

“The end product of its evolution, 7 billion years from now, will be a tiny white dwarf star. This will be about the size of Earth, but much heavier: one teaspoon of white dwarf material weighs about 5 tons,” Decin said.

Using the Alma radio telescope, consisting of 66 individual radio antennas that form a giant virtual telescope with a 10-mile diameter, a team of astronomers analyzed L2 Puppis – estimating its age and evolutionary stages.

“We discovered that L2 Puppis is about 10 billion years old. Five billion years ago, the star was an almost perfect twin of our sun as it is today,” said co-author Ward Homan. “One third of this mass was lost during the evolution of the star. The same will happen with our sun in the very distant future.”

While the sun’s metamorphosis into a red giant will swallow Venus and Mercury, Earth’s ultimate fate is still unknown.

The team encourages further research into the relationship between L2 Puppis and its planet, which could produce valuable information into how the sun’s evolution will impact our Solar System.

Their findings were published Thursday in the journal Astronomy and Astrophysics.



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