Astronomers have announced the discovery of a cold ring of cosmic dust surrounding the star closest to the solar system, the dim red dwarf Proxima Centauri. The discovery suggests that this star, among other things, is home to the nearest Earth-like planet that scientists discovered last year, may be part of a much more complex planetary system than it was previously imagined.
Using data from the Atacama Large Millimeter-Wave Array (ALMA), a radio telescope complex located in the Chilean Atacama Desert, the team was able to identify a faint glow that appeared to be created by a dust belt surrounding Proxima Centauri several hundred million kilometers away. Scientists say that the belt consists of various kinds of space material (stones, dust), as well as ice and has an extremely low temperature of about -230 degrees Celsius, which makes it as cold as the Kuiper belt in our solar system.
Since usually such cosmic belts represent the excess matter of an accretion disk that revolved around the star and served as a source of material for the formation of new planets, it would be logical to assume that there may be significantly more planets inside this star system than we have been able to so far. discover.
"The presence of dust around Proxima is a very important indicator, as it is the first sign to indicate a more complex planetary system, not just one planet," says research project leader Guillem Anglada, astronomer at the Astrophysical Institute of Andalusia.
Further data collection led scientists to make another assumption, according to which the system may be surrounded by an additional, even colder belt of cosmic dust, located around the star at a distance of ten times further. After collecting and analyzing all the data obtained, the astronomers created a small sketch of what the Proxima Centauri system might actually look like (image below). What intrigued the researchers most was that it is located at a distance of about 1.6 astronomical units from the star.
“According to one of the alternative models, at the border of the inner ring, at a distance of about 1.6 AU. That is, there is an unknown source of interference from the star, which may be a planet. A giant planet,”the researchers report in their published results.
This "unknown source" is marked with 3 in the image above. Despite the fact that earlier long-term observations of Proxima Centauri showed no signs of the presence of such a planet, researchers are not yet ready to rule out such a possibility.
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"To confirm or refute this assumption, additional observations will be carried out over the system," the scientists add.
To date, only one planet has been confirmed in the Proxima Centauri system. The presence of Proxima b (as the planet is called) was confirmed in August 2016 by scientists at the European Southern Observatory. At the same time, it was announced that Proxima b is the closest exoplanet to Earth, located in the so-called habitable zone. Just a couple of months later, scientists issued a new statement announcing the completion of calculations that showed that Proxima b could be covered with liquid water and have a thin gaseous atmosphere, which would certainly increase its potential for habitability.
Earlier this year, we found that, despite its initial appeal, Proxim b has a serious flaw. And this disadvantage is the red dwarf, that is, the star around which this planet revolves. The unstable behavior of the dwarf and the stellar wind that it throws towards the planet, most likely, make it a rather harsh habitat. Moreover, some astronomers believe that the power of this stellar wind is so strong that it literally blows away the thin atmosphere of Proxima b, making this world completely lifeless. Not everyone agrees with these conclusions. There are, however, those who consider the planet a real paradise and our future habitat.
It is still impossible to draw final conclusions about Proxima b. And most likely, we will not know the true state of affairs around it until we send there a spacecraft that could collect more scientific data. But on the other hand, we now know about the presence of several rings around the system, which can be an indicator of the presence of even more planets in it. This, in turn, makes a space expedition there even more desirable.
"These results hint that Proxima Centauri has a true planetary system with a rich history of interaction with each other, resulting in the formation of this dust ring," says Anglada.
At the same time, scientists add that constant observation of nearby systems enhances our knowledge of the birth of our own solar system.
"Such observations, combined with studies of protoplanetary disks around young stars, could reveal many details about the processes that led to the formation of the Earth and the solar system about 4.6 billion years ago," says one of the research team at the Astrophysical Institute of Andalusia, an astronomer Pedro Amado.
The findings of the study described today will soon be published in the Astrophysical Journal Letters.
Nikolay Khizhnyak