'Earth clone' likely to be covered in oceans.

The rocky planet Proxima b, located in the habitable zone of its closest star to the Sun, likely contains oceans of liquid water similar to Earth's.

Graphic simulation of the planet Proxima b. Image: ESA.

Astrophysicists at the French National Institute of Scientific Research (CNRS) calculated the size and surface features of the planet Proxima b and concluded that an Earth-like ocean could cover the planet, Phys.org reported yesterday.

The European Space Agency (ESA) announced the discovery of Proxima b last month and stated that it is the first exoplanet that humans could potentially send a robotic probe to in the future. The planet orbits its parent star, Proxima Centauri, four light-years from the Solar System, in the habitable zone. Proxima b has an estimated mass 1.3 times that of Earth and is located 7.5 million kilometers from its parent star.

"Contrary to expectations, the close distance does not necessarily mean that the surface of Proxima b is too hot to allow water to exist in liquid form," the CNRS research team noted.

The star Proxima Centauri is 1,000 times smaller and dimmer than the Sun, suggesting that Proxima b is at the right distance to concentrate the conditions suitable for life. According to the CNRS research team, the planet almost certainly has liquid water on its surface along with some form of life.

The size of an exoplanet is calculated by measuring how much light reaching Earth is blocked by the planet as it passes in front of its parent star. However, since the movement of Proxima b cannot yet be observed, the research team had to rely on simulations to estimate the planet's composition and radius.

They calculated the radius of Proxima b to be around 6,371 km, 0.94 to 1.4 times that of Earth. Assuming a minimum radius of 5,990 km, the planet would be very dense, with a metallic core accounting for two-thirds of its mass, surrounded by a rocky crust. If liquid water existed on the surface, the total amount of water would contribute more than 0.05% of the planet's mass, similar to Earth's ratio of about 0.02%.

In the case of a larger radius of 8,920 km, Proxima b's mass would be evenly distributed between a rocky core in the center and surrounding water. "In this case, Proxima b would be covered by a liquid ocean 200 km deep. Both scenarios would have a thin atmosphere surrounding the planet, similar to Earth, making Proxima b a suitable place for life to develop," the CNRS research team concluded.

According to VNE