Flare star

A flare star is a special kind of star that can suddenly become much brighter for a few minutes. These bright flashes happen without warning and can be seen in many kinds of light, like X-rays and radio waves. Scientists believe these flares happen when magnetic energy builds up and then lets go in the star's atmosphere, like how the Sun sometimes has solar flares.

The first flare stars were found in 1945 by a scientist named A. van Maanen. He saw bright changes in two stars called WX Ursae Majoris and YZ Canis Minoris. The most famous flare star is UV Ceti, which was first seen to flare in 1948. Today, stars like this are called UV Ceti type variable stars.

Most flare stars are cool, dim stars known as red dwarfs, but some even smaller objects called brown dwarfs can also flare. Some stars like our Sun have been seen to flare too, and scientists think hidden planets close to the star might cause these.

Stellar Flare Model

The Sun sometimes has big bursts of light called solar flares. Scientists think that when other stars have sudden brightening called flares, it works in a similar way. Flares happen when magnetic fields in the star's atmosphere twist and snap back into place, releasing energy.

There are a few steps in a flare. First, the star's atmosphere heats up slowly. Then, a quick burst happens where particles get very energetic and release radiation. After that, the star's light increases rapidly before slowly returning to normal. Sometimes, flares can also happen when two stars close together interact, or when a young star has material swirling around it.

Nearby flare stars

Flare stars are very dim but can be seen from far away—up to 1,000 light years from Earth! In 2014, NASA’s Swift satellite saw a big burst of energy from a star called DG Canum Venaticorum. This burst was much brighter than the biggest solar flare we’ve ever seen!

Some of our closest stars are flare stars, too. Proxima Centauri, the star nearest to our Sun, sometimes gets brighter because of its magnetic field. Another close star, Wolf 359, is a tiny, dim star that often bursts with energy. Even Barnard's Star, which seems quiet, was seen to flare in 1998. Young stars like EV Lacertae can have big flares.

Record-setting flares

A very bright flare was seen in 2005. It came from a binary star system called II Peg. Scientists used a satellite called Swift to study it. The flare released energy like the ones from our Sun, including hard X-rays. This helped scientists learn more about how energy works in stars. It is similar to the solar flares we see from the Sun.