Sun surface features
(features on the Sun's surface)
These are some of the numerous terms for features and activity
on the Sun's surface (and above) with a bit about how they are
interrelated. 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:
- sunspot - cool, dark (i.e., less bright) spot, where magnetic field lines emerge.
- facula - bright spot.
- granule - visible bump: convection bubble reaching the surface, occurring across all the Sun's surface.
- supergranule - like a granule 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, but stretching far out from the Sun: the stretch can be a full Sun-diameter; helmet streamers are the typical features of the corona seen during total eclipses.
Beyond:
Solar activity:
- 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 Earth atmosphere. Effects on Earth depend upon size of the eruption and the direction in which it is pointed.
- 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.
(Sun)
Further reading:
https://en.wikipedia.org/wiki/Solar_phenomena
https://en.wikipedia.org/wiki/Sun#Atmosphere
https://en.wikipedia.org/wiki/Stellar_corona
https://en.wikipedia.org/wiki/Coronal_loop
https://en.wikipedia.org/wiki/Category:Sun
http://www.astrosurf.com/luxorion/Media/sun-book-ch2-jenkins.pdf
https://www.britannica.com/place/Sun/Prominences
https://moodle2.units.it/pluginfile.php/423309/mod_resource/content/1/1_Sun-SolarWind_a.pdf
https://www.swpc.noaa.gov/content/space-weather-glossary
https://solarscience.msfc.nasa.gov/
https://www.telescope.com/Solar-Observing-Terminology/p/102837.uts
http://www.igpp.ucla.edu/public/rwalker/ESS200C_2007_winter/The%20Sun.pdf
Index