Scientists spot possible planet circling Proxima Centauri, closest star to solar system

In an intriguing discovery, astronomers have spotted evidence of a possible third planet orbiting Proxima Centauri, the nearest star from the solar system. The candidate planet is dubbed as 'Proxima d', and estimated to be 25% the size of Earth, making it one of the lightest exoplanets ever known, if confirmed. According to space experts, the alien planet orbits extremely close to its parent star, which is roughly calculated to be one-tenth of the distance between the sun and Mercury.

The astronomers came across the potential planet while studying tiny wobbles in the motion of Proxima Centauri that is caused by the gravitational force it exerts while swinging around the star. In addition, the possible planet completes a full orbit of the Sun's nearest neighbour every five days. As per reports, the observations were noted in Chile, using the European Southern Observatory's Very Large Telescope (VLT).

"The discovery shows that our nearest stellar neighbour is packed with interesting new worlds, within reach of further study and future exploration," Joao Faria, a researcher at the Institute of Astrophysics and Space Sciences in Portugal and the lead author of the study said.

The research team followed up the weak signals with Echelle Spectograph for Rocky Exoplanets And Stable Spectroscopic Observations (ESPRESSO) to precisely confirm that the potential planet's actions were the characteristics in itself and not in correspondence to the changes in its parent star. "After obtaining new observations, we were able to confirm this signal as a new planet candidate," Faria said.

Proxima d orbits in a habitable zone

The newly discovered planet candidate orbits Proxima Centauri within 2.4 miles (4kms), which is its habitable zone. This means that Proxima d revolves around the star in an area where the temperature range allows liquid water to exist at the surface of a planet. In addition, the effect of Proxima d's gravity is so negligible that it only causes its parent star to swing at around 40 cm per second (1.44 km/hr).

"This achievement is extremely important. It shows that the radial velocity technique has the potential to unveil a population of light planets, like our own, that are expected to be the most abundant in our galaxy and that can potentially host life as we know it," said Pedro Figueira, ESPRESSO instrument scientist at ESO in Chile.

For a note, Proxima Centauri also hosts two other planets Proxima b and Proxima c. Proxima b is a planet with a mass comparable to that of Earth. It completes orbiting the star in 11 Earth days and also lies in the habitable zone. However, Proxima c takes at least 5 years to orbit Proxima Centauri.

(Image: @NASA/Twitter (representative)