Some 31 light-years away, astronomers have identified an exoplanet similar in size to our planet, orbiting its star at a distance that would allow conditions favorable for life to exist on the planet's surface. Some experts have already dubbed this world as a potential second Earth.
To this day, scientists exploring the galaxy have found a little over 5,200 exoplanets in more than 9,000 different star systems, one of them being a recently found world dubbed Wolf 1069 b, and it is an exciting find, according to experts.
In the hunt for exoplanets, there is nothing more exciting than discovering a planet that could match our planet’s characteristics. Even though only less than two percent of the exoplanets we have found to date have masses than two Earth masses, and dozens of them are located within the so-called habitable zone, a region around a star where liquid water could exist on a planet, given that it is rocky in nature. It is exceptionally difficult to search the galaxy for planets, and observations capable of finding low-mass planets remain a significant challenge.
CARMENES program and the hunt for alien planets
One way to improve the chances of discovering low-mass worlds is to analyze low-mass stars for signatures of orbiting planets. This is just what Diana Kossakowski and her colleagues did within the framework of the CARMENES program. This project, with major contributions from the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, uses the Calar Alto Observatory in Spain to search our galaxy for distant worlds. After gathering data from the star Wolf 1069, scientists discovered a peculiar characteristic. They found a low-amplitude signal from what they interpret as an exoplanet of similar size to Earth. This distant world, dubbed Wolf 1069 b, orbits its star every 15.6 days, at a distance one-fifteenth the distance Earth orbits our sun.
Despite the relative proximity in which the world orbits its star, it only receives around 65 percent of the energy our planet receives from the Sun. This is because Wolf 1069 is a Red Dwarf, some of the smallest and coolest, most abundant planets in the Milky Way Galaxy. This means that Wolf 1069 emits far less radiation and is comparably colder than our Sun. In turn, it places the habitable zone much closer to the star, which means that plants orbiting red dwarfs can be hospitable, despite their proximity to their star.
Wolf 1069 b, Earth 2.0?
The question is just how habitable is Wolf 1069 b? You need more than just liquid water to make it habitable. Just as here on Earth, an atmosphere that can produce a natural greenhouse effect can help raise the average temperature above 250 Kelvin (-23 °C), calculated for Wolf 1069 b. So far, the early data suggests the exoplanet is a basic rocky world. Depending on what kind of atmosphere it has, if it is similar to Earth, then the average temperature on its surface could rise by as much as 286 Kelvin (13 °C), keeping liquid water in a large region on the star-facing side of the planet. This is because it would protect against high-energy electromagnetic radiation and particles from interstellar space or the star.
Whether this is indeed Earth 2.0 remains to be seen. What needs to be taken into consideration is that Red Dwarf. However, the most abundant stars in the galaxy are famous for their activity that produces solar winds and intense ultraviolet radiation. In our solar system, for example, our sun stripped Mars of its atmosphere, rendering its surface barren billions of years ago. However, scientists say this is an unlikely characteristic of Wolf 1069 b. According to astronomers, Wolf 1069 b is also the sixth-closest Earth-mass planet in the habitable zone of its host star. Due to its favorable prospects concerning habitability, it is among a peculiar small group of worlds—such as Proxima Centauri b and TRAPPIST-1 e—to search for biosignatures. Unfortunately, such observations are currently beyond the capabilities of astronomical research.
Find out more at the Max Planck Institute for Astronomy.