Sun surface features
(features on the Sun's surface)
Terms for features and activity on the Sun's surface and some
of their interrelations. Note that the Sun's surface features and
activity are complex and our understanding is still limited and
this outline is incomplete and simplified.
Within the photosphere:
- sunspots - cool, less bright spots, where magnetic field lines emerge.
- facula - bright spot.
- granules - visible bumps: convection bubbles reaching the surface, occurring across all the Sun's surface.
- supergranules - like granules but on a much larger scale: a single supergranule encompasses many granules.
Within the chromosphere:
- spicule - small jet from photosphere into chromosphere.
- Moreton wave - shock wave traveling across the surface, triggered by some types of activity (below).
- plage - bright region of chromosphere, often near sunspots.
Within the corona:
- coronal hole - thin, cool region of corona that emits less X-rays.
- solar prominence - detectable projection into corona, plasma made to glow from magnetic field lines extending into the corona.
- coronal loop - loop-shaped solar prominence which is typical: magnetic field lines do not end, and generally are loops from within the Sun out into the corona and back into the Sun.
- flux rope - coronal loop projections twisted around each other like a rope. It can be ejected during some types of activity (below).
- magnetic arcade - aligned row of coronal loops forming a "tunnel", perhaps a spiraling loop shaped like a spring.
- helmet streamer - large coronal loop, with the top of the arch not slender, rather stretching out away from the Sun: the stretch can be a full Sun diameter; the typical visible part of the corona during a total eclipse.
- solar flare - the term is sometimes used merely to imply a brightening event, and sometimes is meant to imply a solar eruption.
- solar eruption - an event that ejects material, which could be called a heavy blast of solar wind. Often associated with a solar prominence.
- coronal mass ejection (CME) - a very large solar eruption; the term is also used for the material ejected.
- solar particle event (SPE) - effect of some solar eruptions to Earth: particles such as protons reaching Earth vicinity and possibly atmosphere. Effects on Earth depend upon size of the eruption and the direction in which it is aimed.
- geomagnetic storm - effect of some solar eruptions to Earth, including radio and electronic interference, often including auroras.
- solar weather and space weather - general terms for effects of some solar eruptions to Earth, to spacecraft and the rest of the solar system.