Sudden intense brightening of a small part of the Sun's surface, often near a sunspot group. Flares develop in a few minutes and may last several hours, releasing intense X rays and streams of energetic particles. They appear to be connected with changes in the Sun's magnetic fields during the solar cycle. The ejected particles take a day or two to reach the vicinity of Earth, where they can disrupt radio communications and cause auroras, and may pose a radiation hazard to astronauts.
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Star that varies in brightness repeatedly but sporadically, sometimes by more than one magnitude, within a few minutes. The cause is thought to be the eruption of flares like those observed on the Sun but much larger (see solar flare). Proxima Centauri, in Alpha Centauri, the closest star to the Sun, is a flare star.
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Renal flares can raise medical costs: study finds they boost one-year direct medical costs, on average, by almost $26,000.(ACR Annual Meeting, San Francisco)
Feb 01, 2009; PATIENTS WITH lupus nephritis (LN) who experience renal flares incur nearly double the direct medical costs over one year...