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
Horologium (constellation) Horologium (constellation) Horologium is a faint constellation in the southern sky. It was devised by French astronomer Nicolas Louis de Lacaille in 1752, and it remains one of the 88 modern constellations. The constellation's brightest star is Alpha Horologii, an orange giant. R Horologii is a red giant Mira variable with one of the widest ranges in brightness known. Three star systems have exoplanets, while Nu Horologii has a debris disk. The French astronomer Nicolas Louis de Lacaille first described the constellation in French as "l'Horloge à pendule & à secondes" (clock with pendulum and seconds hand) in 1752, after