- an irregular, unusually bright patch on the sun's surface.
Origin of facula
1700–10; < Latin: little torch, equivalent to fac- (stem of fax) torch + -ula -ule
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for facula
Facula, fak′ū-la, n. a spot brighter than the rest of the surface, sometimes seen on the sun's disc:—pl.
He considers it indeed "highly probable that the preparatory sign of a new spot is always a small, bright patch of facula."A Popular History of Astronomy During the Nineteenth Century
Agnes M. (Agnes Mary) Clerke
- any of the bright areas on the sun's surface, usually appearing just before a sunspot and subject to the same 11-year cycle
C18: from Latin: little torch, from fax torch
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- A bright, cloudlike structure on the Sun's surface, ascending several hundred kilometers above the photosphere and often associated with sunspots. Faculae are formed when a strong magnetic field heats a region of the photosphere to higher temperatures than the surrounding area. They occur all over the Sun but are usually only visible near the limb (the outer edge of the Sun's apparent disk), where the photosphere appears dimmer than in the center.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.