Aurora auroras is that an as-yet-undetected body around the dwarf star is throwing off material, as is the case with Jupiter and its moon Io. [[Category:Space plasmas]] [[Category:Arctic geography terminology]] [[Category:Atmospheric optical phenomena]] [[Category:Earth phenomena]] [[Category:Electrical phenomena]] [[Category:Light sources]] [[Category:Plasma physics]] [[Category:Planetary science]] [[Category:Sources of electromagnetic interference]] [[Category:Articles containing video clips]] Aurora An aurora (plural: auroras or aurorae), sometimes referred to as polar lights, northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in the Earth's sky, predominantly seen in the high-latitude regions (around the Arctic and Antarctic). Auroras are produced when the magnetosphere is sufficiently
Sigma Coronae Borealis σ CrB is an RS Canum Venaticorum variable. It varies in brightness by 0.05 magnitudes every 1.139789 days, the same as the orbital period. The brightness changes are caused by variations in surface brightness on the stars, effectively giant sunspots. Variable star designations are not given to stars with Bayer designations, but in this case only one component of σ Coronae Borealis is identified as variable, so it has the designation TZ Coronae Borealis. Sigma Coronae Borealis Sigma Coronae Borealis (σ CrB) is a star system in the constellation of Corona Borealis. It is a quintuple star system containing three