Proxima Centauri, the closest star to Earth at just over four light years away, has long been known for its active M dwarf star behavior. A new study using observations with the Atacama Large Millimeter/submillimeter Array (ALMA) array reveals the star’s extreme flare activity in radio and millimeter wavelengths, providing insights into the particle nature of these flares and potential impacts on habitable-zone planets.
The team, led by Kiana Burton, utilized archival data and new ALMA observations to study Proxima Centauri’s millimeter-wavelength flare activity. Their findings are published in The Astrophysical Journal.
Proxima Centauri is a small star with a strong magnetic field, indicating that its internal structure is likely convective. This makes the star much more active than the sun, which has both convective and nonconvective layers.
The researchers discovered that Proxima Centauri’s flares are short events, ranging from 3 to 16 seconds, but emit a large amount of energy across the electromagnetic spectrum. These outbursts release light energy as well as bursts of particles known as stellar energetic particles.
Depending on the energy and frequency of these flares, nearby planets in the habitable zone might be rendered uninhabitable due to stripped planetary atmospheres lacking necessary ingredients like ozone and water.
According to MacGregor, “Proxima Centauri’s flares are much more powerful than our sun’s activity.” The study represents the first multi-wavelength research using millimeter observations to uncover a new look at the physics of flares.
Source: https://phys.org/news/2025-03-small-star-mighty-flares-alma.html