The star closest to our sun turns out to be home to not two, but three planets!

The nearest star Proxima Centauri turns out to be home to another planet. Researchers write this in a study published today in Astronomy & Astrophysics has been published. We already knew that there were two planets orbiting the star. But we can now add a third planet to that list.

Discovery

In the new study, astronomers observed the galaxy using the Very Large Telescope (VLT) at the European Southern Observatory (ESO). And to their surprise, they came across the interesting evidence of a signal corresponding to an object with a five-day orbital period. Following follow-up observations with a new, more accurate instrument from ESO’s VLT – the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) – indeed, the researchers cannot help but conclude that Proxima Centauri is home to another planet. The new candidate planet has been named Proxima d.

Proximity to

This newly discovered planet appears to orbit Proxima Centauri at a distance of about four million kilometers. For your imaging, that’s less than a tenth of the distance between Mercury and the sun. The planet is located between the star and its habitable zone – the region around a star where liquid water can exist on a planet’s surface. The planet takes only five days to make one orbit around Proxima Centauri.

Lightest exoplanet

After further analysis, Proxima d appears to have only a quarter of the mass of the Earth. This makes the planet a true lightweight and also one of the lightest exoplanets ever discovered. “The discovery shows that our nearest stellar neighbor is awash in interesting new worlds, which lie within the scope of further research and exploration,” said study leader João Faria.

Proxima Centauri

The discovery makes the star Proxima Centauri even more interesting than it already was. This is partly because the star is located at a relatively short distance from Earth. For example, the star is only 4 light-years away, making it closest to our sun. As mentioned, it was already known that this star is home to two planets, one of which could look quite similar to Earth. Proxima b has a mass comparable to that of Earth and completes one orbit around the star every 11 days. In addition, Proxima Centauri orbits the planet Proxima c, which orbits a wider orbit with an orbital period of five years.

Living on Proxima b?
Proxima b is the closest exoplanet discovered to date. To top it all off, this planet is also in the habitable zone (meaning that, judging by its distance from its parent star, it could theoretically have the water so vital to life as we know it). Shortly after the discovery of Proxima b there was great excitement. Because the nearest exoplanet could harbor life! However, many astronomers have now come back to this, as study after study suggests that the red dwarf star Proxima Centauri is particularly restless and regularly produces violent solar flares that have evaporated any atmosphere or ocean on Proxima b and possibly even sterilized its surface. .

According to the researchers, the discovery of a third planet around Proxima Centauri is not only fascinating, it also shows the potential of the new ESPRESSO instrument. “We can now detect a population of planets as light as our own,” said researcher Pedro Figueira. Planets like these are expected to be the most abundant in our Milky Way galaxy and could potentially harbor life as we know it. “Our findings clearly show what ESPRESSO is capable of,” adds Faria. “It makes me curious about what the instrument will be able to detect in the future.”