Proxima Centauri does not stop surprising us. The ALMA Observatory located in Chile has detected cold dust around the star closest to the solar system, Proxima Centauri, which reveals the first indication that this star has a much more complex planetary system than we thought until now. This cold powder outer belt, which is a few hundred million kilometers from Proxima Centauri, could be made of rock and ice particles that could not form planets.
Regarding the star, Proxima Centauri is a tenuous red dwarf located only 4 light-years away from Earth in the southern constellation Centaurus (The Centaur). The temperate world Proxima b, discovered in 2016 orbits this star, which makes it the planet closest to the solar system. But, in light of this ALMA discovery, this system is not made up of a solitary planet.
According to the study, led by Spanish researcher Guillem Anglada of the Institute of Astrophysics of Andalusia (Spain), the mass of the cold dust found is one hundredth of the mass of the Earth, and the particles of dust and rock would have an estimated temperature of -230ºC approximately, as cold as those of the Kuiper belt in the outer solar system.
“The dust around Próxima is important because, after the discovery of the terrestrial planet Próxima b, it is the first indication of the presence of a complex planetary system (made up of more than one planet) around the star closest to our Sun” explains Anglada.
The dust belts, to which we refer, are the remains of material that did not form larger bodies, such as planets. The rock and ice particles in these belts vary in size from the smallest dust grain – smaller than a millimeter in width – to asteroid- like bodies many kilometers in diameter.
In the ALMA data there are indications of a second belt of cold dust, located ten times farther away. If confirmed, the nature of an outer belt ‘is intriguing’, given its cold environment and away from a star that is colder and weaker than the Sun. Both belts are much further away from Proxima Centauri than the planet Proxima b that orbits only four million kilometers from its parent star.
“This result suggests that Proxima Centauri can have a multi-planetary system with a rich history of interactions that resulted in the formation of a dust belt,” says Anglada.
The scientists hope that the next studies carried out from now on will help to collect new data in order to identify possible additional planets not yet detected.
A very interesting planet
The planetary system of Proxima Centauri is also particularly attractive because there are plans (the Starshot project, without going any further), for the future direct exploration of the system with microprobes connected to laser-powered candles. Here, knowledge of the dust environment around the star is essential to plan such a mission. So we’re just at the beginning:
“These early results show that ALMA can detect dust structures orbiting Proxima, and the additional observations will give us a more detailed picture of Proxima’s planetary system.” In combination with the study of protoplanetary disks around of the young stars, many of the details of the processes that led to the formation of the Earth will be revealed and the Solar System about 4600 million years ago. What we are seeing now is just the appetizer compared to what is coming!“, highlights Pedro Amado, co-author of the work.