M 92

According to newer sources, M92 is about 26,000 light years distant, only little more than its brighter apparent neighbor M13. From its HRD (or CMD), it may be a bit younger than M13 as its turnoff point is shifted to the brighter and bluer end. M92 is a splendid object, visible to the naked eye under very good conditions and a showpiece for every optics. It is only slightly less bright but about 1/3 less extended than M13: its 11.2' angular extension corresponds to a true diameter of 85 light years, and may have a mass of up to 330,000 suns.

Only about 16 variables have been discovered in this globular, 14 of which are of RR Lyrae type, while one of them is one of the very few eclipsing binaries in globular clusters, of W Ursae Majoris type. Although Burnham claims it is not well understood why eclipsing binaries are so rare in globulars, it appears to the present author that there may be a simple answer: In these dense stellar agglomerates, close encounters occur frequently, so that binary systems will be disturbed, and on the long term, will be destroyed.

M92 is approaching us at 112 km/sec.

Right ascension	17 : 16.5 (hours : minutes)
Declination	+43 : 10 (degrees : minutes)
Distance	??? (light-years*10^3)
Visual magnitude	6.3