The Spanish CARMENES telescope found an exoplanet just 26 light-years from our home. It’s a hot super-Earth that orbits a red dwarf in frightening proximity — it’s just 2.5 million km (1.5 million miles) from its star, the equivalent of just two-hundredths of the distance between our planet and the Sun. If you need a more precise comparison, Earth is 150 million km (93 million miles) from the Sun. Although its surface is scorching hot, its atmosphere appears colder and much lighter than our sister planet, Venus. Astronomers are invigorated by this find, as they believe the planet could shed light on the formation and composition of potentially habitable planets.
The science and other stuff to know
The search for exoplanets is a relatively modern field of astronomy. Various methods enable the identification of planets that orbit distant stars so astronomers can understand these alien worlds’ dynamics, formations, and structures. The holy grail of this research? To analyze the planet’s physical and chemical conditions to determine if they are habitable.
The discovery of this planet, Gliese 486b, was possible with planetary transit. To identify alien worlds via planetary transit, scientists analyze the variations in the light spectrum of a star. If valleys in its range correspond to a periodic drop in luminosity, we face a transit. In other words, an opaque object — such as a planet — is passing in front of the star, partially eclipsing it and reducing the light flow.
In this case, scientists observed a star known as Gliese 486, an ancient red dwarf. One of the planets that orbit it is this super-Earth. Its period of revolution around its mother star is barely one and a half Earth days. Due to its orbital proximity to the star, Gliese 486b could suffer from a tidal coupling effect, which means that its day and year are of the same length, causing the planet to always shows the same face to its star, as is the case with the Moon and the Earth.
The characteristics of its atmosphere arouse curiosity in researchers. Why? Because the planetary models we have indicate that the radiation Gliese 486b should dismantle the gaseous layer surrounding it. However, it isn’t what astronomers observe in this great wandering Venus. Instead, its atmosphere seems well consolidated, a characteristic that experts attribute to the gravity that its great mass exerts.
Researchers believe that by studying the properties of this and other exoplanets in more detail, they could better understand how rocky planets interact with their atmospheres and how radiation from their stars affects them. The central objective? To find a model that allows us to find habitable planets more accurately.
There is still a long way to go in our quest for a complete understanding of all the possible worlds that await us.
Experts hope to get more — and more accurate — data on Gliese 486b and other exoplanets with similar characteristics with new instruments, such as the James Webb Space Telescope (JWST). Only with equally or more sophisticated devices can we make precise measurements that provide valuable information about its atmosphere and composition for us to draw practical conclusions.