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
Phoenix (constellation) dim to warrant their letters. A different star was subsequently labelled Psi Phoenicis, while the other two designations fell out of use. Ankaa is the brightest star in the constellation. It is an orange giant of apparent visual magnitude 2.37 and spectral type K0.5IIIb, 77 light years distant from Earth and orbited by a secondary object about which little is known. Lying close by Ankaa is Kappa Phoenicis, a main sequence star of spectral type A5IVn and apparent magnitude 3.90. Located centrally in the asterism, Beta Phoenicis is the second brightest star in the constellation and another binary star. Together