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Kemble 2

‘Little Cassiopeia’, ‘Little Queen’

A small asterism in the constellation of Draco, falling between the stars Batentaban Borealis (Chi Draconis) and Upsilon Draconis to its southeast. This is a faint group of stars (the brightest only reaching magnitude +6.82) and so it is not visible without optical aid.

Magnifying this part of the sky, however, reveals a formation of six stars whose shape is remarkably similar to that of the constellation of Cassiopeia (or, more precisely, to the 'W'-shaped formation known as Cassiopeia's Chair). Thus the group designated Kemble 2 is often known informally as the 'Little Cassiopeia' or the 'Little Queen'. The entire formation spans just under nineteen minutes of arc (as compared with more than thirteen degrees for the true constellation of Cassiopeia). The 'Little Cassiopeia', then, is approximately one fortieth the angular size of its more prominent namesake.

Imagery provided by Aladin sky atlas

Kemble 2 is not a true cluster or grouping of stars, and its members are very widely separated in space while lying on the same line of sight from Earth. The closest of these stars to the Sun is yellow HD 173127 at a distance of some 207 light years (this star occupies the easternmost point of the 'W', the equivalent position to the star Segin in the full-sized Cassiopeia). The most distant of the set is faint orange SAO 9175, lying near the centre of the 'W' like Castula in Cassiopeia, at a distance approaching three thousand light years.

Kemble 2 takes its name from Father Lucian Kemble, who identified several small and curious asterisms in the northern sky, and three of these formations carry 'Kemble' numbers. Kemble 1, or Kemble's Cascade, is a nearly straight line of stars near the cluster Collinder 45 in Camelopardalis. Kemble 3, called Kemble's Kite, is a grouping in eastern Cassiopeia, forming a diamond-shaped kite with a string of stars representing its tail.