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Planet spotted orbiting Barnard's star just 6 light years away

Astronomers have detected an exoplanet around Barnard鈥檚 star, one of the sun鈥檚 closest neighbours, but it is too hot for liquid water or life

By Alex Wilkins

1 October 2024

Artist鈥檚 impression of Barnard鈥檚 star b, a planet in orbit around Barnard鈥檚 star

ESO/M. Kornmesser

One of the sun鈥檚 closest neighbours, Barnard鈥檚 star, appears to have at least one planet orbiting it, as well as another three possible planets that need further confirmation.

Astronomers have been looking for planets around Barnard鈥檚 star, which at 5.96 light years away is the next-closest star to us after the three stars in the Alpha Centauri system, since the 1960s.

In 2018, researchers claimed to have found a planet that was at least three times larger than Earth, which they called Barnard鈥檚 star b, but a follow-up analysis showed that the signals of the apparent planet were actually caused by higher than expected stellar activity.

Now, at the Canary Islands Institute of Astrophysics and his colleagues say they have found a new Barnard鈥檚 star b, which is around 40 per cent as massive as Earth.

The planet is much closer to its star than any planets in our solar system, completing an orbit in just over three Earth days. This also means its surface is too hot for liquid water or life, with a temperature of around 125掳C (257掳F).

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Gonz谩lez Hern谩ndez and his team found the star by watching for tiny wobbles in the position of Barnard鈥檚 star caused by the gravity of its orbiting planet, using an instrument on the European Southern Observatory鈥檚 Very Large Telescope in Chile called ESPRESSO.

They also found evidence for three more planets orbiting the star. However, the signals weren鈥檛 strong enough to say for certain, so they will need further observations to confirm it.

鈥淭hese are very tricky detections, and it’s always hard because you have the activity of the star, the stellar magnetic fields, which are rotating with the star,鈥 says at the National University of San Mart铆n in Argentina. Gonz谩lez Hern谩ndez and his team have been thorough in checking that their observations were from a planet, but there could always be 鈥渦nknown unknowns鈥, says Fernando D铆az. Truly confirming this will require data from another telescope, which could take years of observations, he says.

Journal reference:

Astronomy & Astrophysics

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