Scientists Find the Closest Rocky Planet to Ours in Our Solar System

WASHINGTON – Barnard’s Star is a red dwarf, the smallest type of regular star and much smaller and less luminous than our sun. At a distance of about 6 light years, it is the closest single star – not orbiting another star – to our solar system.

Cosmically, this star is all around us. So, scientists who wanted to study a possible habitable world nearby were excited to discover the first confirmed planet orbiting a star Barnard, a rocky planet with a mass of about 40% that of Earth.

Although this planet, which is very close to Barnard’s star, has a surface temperature too high to support life, the researchers found what they called “strong glimpses” of three other planets around Barnard’s star might be better candidates.

The diameter of the discovered planet, called Barnard b, is thought to be about three-quarters that of Earth, which is about 6,000 miles (9,700 km).

“This is one of the smallest planets ever discovered,” outside our solar system, said astronomer Jonay González Hernández of the Instituto de Astrofísica de Canarias in Tenerife, Spain, lead author of the study. published this week in the journal Astronomy & Astrophysics, opens a new tab.

Among the planets in our solar system, only Mars and Mercury are smaller.

Barnard b, with a surface temperature of about 275 degrees Fahrenheit (125 degrees Celsius), orbits Barnard’s star in just three Earth days at a distance 20 times closer to the system’s innermost planet our sun, Mercury, to the sun.

Planets outside our solar system are called exoplanets. Scientists looking for exoplanets that could harbor life look for exoplanets that are in the “habitable zone” around the star, where it is neither too hot nor too cold, and where liquid water can exist on the surface of the planet.

The researchers used an instrument called ESPRESSO on the European Southern Observatory’s Very Large Telescope located in Chile to find the planet.

The other three possible planets orbiting Barnard’s star all appear to be rocky and smaller than Earth, between 20-30% of Earth’s mass.

The hope is that at least one of these planets could be close to the habitable zone. If confirmed, it would be the only star known to have a multi-planetary system made up of planets smaller than Earth.

Barnard’s Star, in the constellation Ophiuchus, has a mass of about 16% of the Sun’s mass, a diameter of 19% of the Sun’s mass, and is much less hot. It is thought to be twice as old as the Sun.

“Because it is so cool and small, this star is very faint, so its habitable zone is much closer to the star than to the Sun,” said the astronomer Instituto de Astrofísica de Canarias and study co-author Alejandro Suárez Mascareño “This star is also very quiet. Although some red dwarfs have been found to light up quite often, Barnard’s star has not.”

The closer an exoplanet is to us, the easier it is to study it. Low-mass rocky planets are easier to find around red dwarfs, the most common type of star in our Milky Way, than around larger stars.

Only three stars in the Alpha Centauri system, located about 4 light years away, are closer to our solar system than Barnard’s star. A light year is the distance that light travels in a year, 5.9 trillion miles (9.5 trillion km).

Two exoplanets have been discovered in the Alpha Centauri system, both orbiting the red dwarf star Proxima Centauri. One of them has about the same mass as Earth. The other is about 25% the mass of Earth.

In science fiction, traveling at the speed of light is very common. In reality, it is far beyond human capabilities, although research projects such as Breakthrough Starshot are exploring the possibility of interstellar travel. Barnard’s Star and Alpha Centauri may be on your wish list for the future.

“Although both are very close in terms of astronomy, they are beyond the reach of any human technology. However, if a project like Breakthrough Starshot succeeds, these may be some of the first targets,” said Mascareño.