In another solar system 26 light-years away, there is a red dwarf, a small and relatively cool star, called Gliese 486. Scientists have discovered that around the star there are so-called exoplanets – Gliese 486 b. Now researchers using different methods have arrived at what they look like.
It is an Earth-like planet in that it is made of stone and metal and has the same density as the Earth, says Alexis Brandeiker, astronomer in astronomy at Stockholm University.
But this planet is closer to its star than Earth. While the Earth orbits its star in one year, it takes only 1.5 days for the exoplanet to orbit its red dwarf. Hence, it is very hot on the planet – around 400 ° C.
Researchers use indirect methods
To get to the characteristics of the planet, the scientists used two different methods. One method involves researchers checking the star’s brightness. It is not possible to see the planet directly. But with the red planet as the backdrop, the planet’s contours appear more and more each time it passes.
– Then you can measure its size. Alexis Brandaker says the larger the planet, the more light it blocks.
But in this way, one cannot know how heavy the planet is, and how massive it is. To find out, scientists are measuring how the planet’s gravitational force affects the star.
The mass of a planet affects how the star moves. By measuring how the star moves, you can find out the mass of the planet.
This particular planet is 30 percent larger than Earth, but three times heavier.
Unique conditions for the study atmosphere
The exoplanet also has unique conditions for researchers to be able to study whether a planet has an atmosphere and how habitable it is.
Many planets in our galaxy revolve around such red dwarf stars. One of the questions that people are most interested in answering is whether planets have atmospheres, Alexis Brandaker says.
These red dwarfs are fainter but also more active. This means that they have large volcanic eruptions that send large amounts of radiation to the planets. Therefore, it is uncertain whether these planets are able to maintain their atmospheres.
“Because this star is so close to the sun, it is one of the closest exoplanets that we know of outside the solar system, and it is a good candidate for use in future instruments that can measure the atmosphere,” says Alexis Brandeker.
For the curious who have access to the telescope, an exoplanet can be seen no matter where you are on Earth, according to the researchers.
The study was published in Science.