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Sun
The Sun, also known as Star Sol, is the G2 yellow dwarf star at the center of the Solar System, about 4.57 billion years old.
Sun path
The sun path, or path of the Sun, is the apparent arc the Sun traces across the local sky, shifting through the year and depending on latitude and date.
Supergranulation
Supergranulation is a cellular pattern of mostly horizontal flows on the Sun's surface, with cells about 30,000 km across that last one to two days.
Tachocline
The tachocline is a thin shear layer inside the Sun, about 0.7 solar radii from the center, where differential rotation transitions to uniform rotation in the interior.
Transition region (Sun)
The transition region is a thin layer of the Sun's atmosphere separating the hot corona from the cooler chromosphere, where the temperature drops from about 1,000,000°C to 20,000°C.
Transition Region and Coronal Explorer
The Transition Region and Coronal Explorer (TRACE) was a NASA Small Explorer satellite that imaged the Sun's transition region and corona in ultraviolet light from 1998 to 2010.
Wolf number
The Wolf number, also called the relative sunspot number, is a daily index of solar activity computed from sunspot counts, devised by Rudolf Wolf in 1848.