Space & Astronomy
Proxima b is more Earth-like than we thought
By T.K. Randall
May 30, 2020 · 11 comments
An artist's impression of the surface of Proxima b. Image Credit: ESO / M. Kornmesser
The closest known extrasolar planet may also be one of the most Earth-like worlds ever discovered.
Situated only 4.2 light years away in orbit around the red dwarf star Proxima Centauri, the terrestrial planet Proxima b, which was first discovered back in August 2016, could be a genuine Earth 2.0.
Previous studies had suggested that this neighboring world was around 1.3 times the mass of the Earth, but now new observations have revealed that it is actually much closer than that.
Key to this revelation was the Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO) instrument that is currently mounted on the European Southern Observatory's (ESO) Very Large Telescope in Chile.
"We were already very happy with the performance of HARPS (High Accuracy Radial Velocity Planet Searcher), which has been responsible for discovering hundreds of exoplanets over the last 17 years," said study co-author Francesco Pepe from the University of Geneva.
"We're really pleased that ESPRESSO can produce even better measurements, and it's gratifying and [a] just reward for the teamwork lasting nearly 10 years."
With the increased accuracy of the new instrument, it has turned out that Proxima b is only 17% more massive than the Earth, making it a much more likely candidate for supporting life.
Given its distance from its parent star, it is also possible that liquid water could exist on its surface.
"ESPRESSO has made it possible to measure the mass of the planet with a precision of over one-tenth of the mass of Earth," said astrophysicist Michel Mayor. "It's completely unheard of."
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