Space. Dozens of “wandering planets” discovered in our galaxy

A unique discovery. An international team of scientists led by astrophysicists in particular from the University of Bordeaux has uncovered the largest group of wandering planets ever discovered in the constellations Scorpio and Serpentarius. The results of their research, in which the total of twenty years of images and data recorded by the European Southern Observatory (ESO) telescope and the European satellite Gaia, have been published in the acclaimed scientific journal Nature astronomy.

What are these wandering planets? And why are they so special? Explanations.

What is a “wandering planet”?

Wandering planets, nomadic planets, wandering planets or “free-floating planets” in English … There is no shortage of concepts to denote these planets, which do not orbit any star, and which therefore move freely, without affiliation, in the galaxy. They do not know any sunrise or sunset.

These celestial bodies were first seen in the 2000s.

Why are they roaming around the galaxy?

To date, astronomers know little about these amazing planets and do not yet understand why they move freely through the Milky Way. Some believe that they may have been expelled from their own star systems. Others believe they are the result of the death of gaseous planets, which, when they disappeared, were too small to lead to the formation of a star.

Animation produced by the authors of the study:

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Why is this recent discovery unique?

In a press release from the European Southern Observatory, the researchers behind the recent discovery of migrating planets assure that it is the largest cluster of bodies of this type that has ever been excavated. By studying thousands of images of a group of about 4,000 planets, scientists have actually found dozens of wandering planets whose masses are close to our neighbor Jupiter and located in the constellations Scorpius and Serpentarius.

This is a real feat as these planets are very difficult to observe. It’s actually impossible to detect them by studying the star’s influence on them, as one usually does for exoplanets … since they do not orbit stars.

Astronomers are therefore forced to flush them out directly on the images taken with telescopes. But for that, put your finger on young wandering planets (less than ten million years old), which are still warm due to their “recent” formation and therefore bright enough to be observed.

“We measured very small motions, the color and brightness of tens of thousands of sources in a large area,” explains Núria Miret-Roig, an astronomer at the Bordeaux Astrophysics Laboratory.

Between 70 and 170 wandering planets

Result: 70 wandering planets. “We did not know how many we were going to find and we are very excited to have found so many,” rejoices Núria Miret-Roig.

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Surrounded in red, the wandering planets discovered by Bordeaux scientists

Nearby WorldHervé Bouy, professor at the University of Bordeaux and co-author of the study published in Natureestimates that the number of discovered wandering planets may be even greater.

If we are pessimistic and estimate the age of all objects to be 8 million years, we have 70 wandering planets. If we are optimistic and give them 1 million years, then we will be 170. The truth must lie between the two.

Herve Bouy

A discovery to teach us more about these nomadic planets

Thanks to the discovery of at least 70 wandering planets, astronomers should have many new elements to learn more about the origin and formation of these strange celestial bodies.

The researchers behind the study now hope to be able to study these hikers with greater precision thanks to future, more efficient technological tools. In an article also published on the website of Nature, Núria Miret-Roig explains that the James Webb Telescope could provide answers to scientists on these newly discovered planets, especially on the aspect of their atmosphere. Scientists are also awaiting the launch of the new Extremely Large Telescope (ELT) telescope to be commissioned by the European Southern Observatory in the Chilean desert.

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