Proxima Centauri , the star closest to our Sun , is known to host at least one terrestrial planet candidate in a temperate orbit .
Here we report the ALMA detection of the star at 1.3 mm wavelength and the discovery of a belt of dust orbiting around it at distances ranging between 1 and 4 au , approximately .
Given the low luminosity of the Proxima Centauri star , we estimate a characteristic temperature of about 40 K for this dust , which might constitute the dust component of a small-scale analog to our solar system Kuiper belt .
The estimated total mass , including dust and bodies up to 50 km in size , is of the order of 0.01 Earth masses , which is similar to that of the solar Kuiper belt .
Our data also show a hint of warmer dust closer to the star .
We also find signs of two additional features that might be associated with the Proxima Centauri system , which , however , still require further observations to be confirmed : an outer extremely cold ( about 10 K ) belt around the star at about 30 au , whose orbital plane is tilted about 45 degrees with respect to the plane of the sky ; and additionally , we marginally detect a compact 1.3 mm emission source at a projected distance of about 1.2 arcsec from the star , whose nature is still unknown .