Editing Sunspot (section)

=== Morphology ===
[[File:Sunspot from Hinode in G band (4305) 2007-04-30 T001456.gif|thumb|A decaying sunspot shown over the course of two hours. The umbra is separated into two pieces within the penumbra by a light bridge.<ref name="felipe16">{{cite journal |last1=Felipe |first1=T. |last2=Collados |first2=M. |last3=Khomenko |first3=E. |last4=Kuckein |first4=C. |last5=Asensio Ramos |first5=A. |last6=Balthasar |first6=H. |last7=Berkefeld |first7=T. |last8=Denker |first8=C. |last9=Feller |first9=A. |last10=Franz |first10=M. |last11=Hofmann |first11=A. |last12=Joshi |first12=J. |last13=Kiess |first13=C. |last14=Lagg |first14=A. |last15=Nicklas |first15=H. |last16=Orozco Suárez |first16=D. |last17=Pastor Yabar |first17=A. |last18=Rezaei |first18=R. |last19=Schlichenmaier |first19=R. |last20=Schmidt |first20=D. |last21=Schmidt |first21=W. |last22=Sigwarth |first22=M. |last23=Sobotka |first23=M. |last24=Solanki |first24=S. K. |last25=Soltau |first25=D. |last26=Staude |first26=J. |last27=Strassmeier |first27=K. G. |last28=Volkmer |first28=R. |last29=von der Lühe |first29=O. |last30=Waldmann |first30=T. |title=Three-dimensional structure of a sunspot light bridge |journal=Astronomy & Astrophysics |date=December 2016 |volume=596 |pages=A59 |doi=10.1051/0004-6361/201629586 |arxiv=1611.04803 |bibcode=2016A&A...596A..59F |s2cid=119419693 |url=https://www.aanda.org/articles/aa/pdf/2016/12/aa29586-16.pdf |access-date=5 January 2022}}</ref> Solar pores are also visible to the left of the penumbra.]]
Sunspots have two main structures: a central [[wikt:umbra|umbra]] and a surrounding [[wikt:penumbra|penumbra]]. The umbra is the darkest region of a sunspot and is where the magnetic field is strongest and approximately vertical, or [[Normal (geometry)|normal]], to the Sun's surface, or [[photosphere]]. The umbra may be surrounded completely or only partially by a brighter region known as the penumbra.<ref name="schlichenmaier10">{{cite journal |last1=Schlichenmaier |first1=R. |last2=Rezaei |first2=R. |last3=Bello González |first3=N. |last4=Waldmann |first4=T. A. |title=The formation of a sunspot penumbra |journal=Astronomy and Astrophysics |date=March 2010 |volume=512 |pages=L1 |doi=10.1051/0004-6361/201014112|bibcode=2010A&A...512L...1S |doi-access=free }}</ref> The penumbra is composed of radially elongated structures known as penumbral filaments and has a more inclined magnetic field than the umbra.<ref>{{cite journal |last1=Mathew |first1=S. K. |last2=Lagg |first2=A. |last3=Solanki |first3=S. K. |last4=Collados |first4=M. |last5=Borrero |first5=J. M. |last6=Berdyugina |first6=S. |last7=Krupp |first7=N. |last8=Woch |first8=J. |last9=Frutiger |first9=C. |title=Three dimensional structure of a regular sunspot from the inversion of IR Stokes profiles |journal=Astronomy & Astrophysics |date=November 2003 |volume=410 |issue=2 |pages=695–710 |doi=10.1051/0004-6361:20031282|bibcode=2003A&A...410..695M |doi-access=free }}</ref> Within sunspot groups, multiple umbrae may be surrounded by a single, continuous penumbra.

The temperature of the umbra is roughly 3000–4500&nbsp;K, in contrast to the surrounding material at about 5780&nbsp;K, leaving sunspots clearly visible as dark spots. This is because the [[luminance]] of a heated [[black body]] (closely approximated by the photosphere) at these temperatures varies greatly with temperature. Isolated from the surrounding photosphere, a single sunspot would shine brighter than the full [[moon]], with a crimson-orange color.<ref>{{cite web|url=http://image.gsfc.nasa.gov/poetry/workbook/sunspot.html|title=Sunspots|publisher=NASA|date=1 April 1998|access-date=22 February 2013|archive-date=3 April 2013|archive-url=https://archive.today/20130403033824/http://image.gsfc.nasa.gov/poetry/workbook/sunspot.html|url-status=dead}}</ref>

In some forming and decaying sunspots, relatively narrow regions of bright material appear penetrating into or completely dividing an umbra. These formations, referred to as light bridges, have been found to have a weaker, more tilted magnetic field compared to the umbra at the same height in the photosphere. Higher in the photosphere, the light bridge magnetic field merges and becomes comparable to that of the umbra. [[Gas pressure]] in light bridges has also been found to dominate over [[magnetic pressure]], and convective motions have been detected.<ref name="felipe16" />

The [[Wilson effect]] implies that sunspots are depressions on the Sun's surface.