Berlin, 13 February
A team of astronomers using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile has found evidence of another planet orbiting Proxima Centauri, the closest star to our Solar System.
Proxima Centauri is the closest star to the Sun, located more than four light years away.
The newly discovered planet, named Proxima d, orbits Proxima Centauri at a distance of about four million kilometers, less than a tenth of Mercury’s distance from the Sun.
This candidate planet is the third detected in the system and the lightest ever found orbiting this star. With only a quarter of Earth’s mass, it is also one of the lightest exoplanets ever discovered.
These findings were published in Astronomy & Astrophysics journal.
“This discovery suggests that our nearest stellar neighbor appears to be packed with exciting new worlds, within reach of further study and future exploration,” Joao Faria, a researcher at the Instituto de Astrophysica e Ciencias do Espaco, Portugal, said in a statement.
Proxima d orbits between the star and the habitable zone — the area around a star where liquid water can exist on a planet’s surface — and takes only five days to complete one orbit around Proxima Centauri.
The star system is already known to host two other planets: Proxima b, a planet with a mass comparable to Earth that orbits the star every 11 days and is in the habitable zone, and candidate Proxima c, which is in a five-year longer orbit around the star. .
Proxima b was discovered several years ago using the HARPS instrument on the ESO 3.6 meter telescope.
This discovery was confirmed in 2020 when scientists observed the Proxima system with a new instrument on ESO’s higher-precision VLT, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO).
It was during these more recent VLT observations that astronomers saw the first hint of a signal corresponding to an object with a five-day orbit. Because the signal was so weak, the team had to carry out follow-up observations with ESPRESSO to confirm that it was caused by a planet, and not just a change in the star itself.
“After getting new observations, we can confirm this signal as a candidate for a new planet,” said Faria.
At just a quarter Earth’s mass, Proxima d is also the lightest exoplanet technique ever measured using radial velocity, surpassing the newly discovered planet in the L 98-59 planetary system. IANS
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