Beta Boötis the ROSAT satellite was used to observe an X-ray flare on Beta Boötis, which released an estimated . This was the first such observation for a low-activity star of this type. The flare may be explained by an as yet unobserved M-type dwarf companion star. Beta Boötis Beta Boötis (β Boötis, abbreviated Beta Boo, β Boo), also named Nekkar, is a star in the northern constellation of Boötes. It has an apparent visual magnitude of 3.5, making it one of the brighter members of the constellation. In the modern constellation, it marks the head of Boötis the herdsman. Based upon
Gemini (constellation) light-years from Earth, and the secondary is of magnitude 8. 38 Gem, a binary star, is also divisible in small amateur telescopes, 84 light-years from Earth. The primary is a white star of magnitude 4.8 and the secondary is a yellow star of magnitude 7.8. U Gem is a dwarf nova type cataclysmic variable discovered by J. R. Hind in 1855. Mu Gem is the Bayer designation for a star in the northern constellation of Gemini. It has the traditional name Tejat Posterior, which means back foot, because it is the foot of Castor, one of the Gemini twins. Since