- Polygon (Wikipedia)
In geometry, a polygon (/ˈpɒlɪɡɒn/) is a plane figure made up of line segments connected to form a closed polygonal chain.
- Betelgeuse (stars.astro.illinois.edu)
BETELGEUSE (Alpha Orionis). The great star Betelgeuse is one of the two that dominate mighty Orion of northern winter, the other Rigel, the pair respectively also called Alpha and Beta Orionis.
- Betelgeuse (Wikipedia)
Betelgeuse is a red supergiant star of spectral type M1-2 and one of the largest visible to the naked eye. It is usually the tenth-brightest star in the night sky and, after Rigel, the second-brightest in the constellation of Orion. It is a distinctly reddish, semiregular variable star whose apparent magnitude, varying between +0.0 and +1.6, has the widest range displayed by any first-magnitude star. At near-infrared wavelengths, Betelgeuse is the brightest star in the night sky. Its Bayer designation is α Orionis, Latinised to Alpha Orionis and abbreviated Alpha Ori or α Ori.
