Editing Sunspot (section)

== Starspot ==
{{main|Starspot}}
In 1947, G. E. Kron proposed that [[starspot]]s were the reason for periodic changes in brightness on [[red dwarfs]].<ref name="strassmeier"/> Since the mid-1990s, starspot observations have been made using increasingly powerful techniques yielding more and more detail: [[Photometry (astronomy)|photometry]] showed starspot growth and decay and showed cyclic behavior similar to the Sun's; [[spectroscopy]] examined the structure of starspot regions by analyzing variations in spectral line splitting due to the Zeeman effect; [[Doppler imaging]] showed differential rotation of spots for several stars and distributions different from the Sun's; spectral line analysis measured the temperature range of spots and the stellar surfaces. For example, in 1999, Strassmeier reported the largest cool starspot ever seen rotating the giant [[Stellar classification#Class K|K0]]&nbsp;star [[XX Trianguli]] (HD&nbsp;12545) with a temperature of {{convert|3500|K|C}}, together with a warm spot of {{convert|4800|K|C}}.<ref name="strassmeier"/><ref>{{cite web |url=http://www.aip.de/groups/activity/pics/DI/12545s4e.gif |title=Derived images showing rotation of cool and warm starspots |publisher=Leibniz Institute for Astrophysics |access-date=2013-01-14 |archive-url=https://web.archive.org/web/20100529200045/http://www.aip.de/groups/activity/pics/DI/12545s4e.gif |archive-date=29 May 2010 |url-status=dead }}</ref>
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