Xi, where the asterism crosses over to Mu Serpentis in the head, is a triple star system[2] located approximately 105 parsecs away.[45] Two of the stars, with a combined apparent magnitude of around 3.5, form a spectroscopic binary with an angular separation of only 2.2 milliarcseconds,[46] and thus cannot be resolved with modern equipment. The primary is a white giant with an excess of strontium.[45] Theta, forming the tip of the tail, is also a multiple system, consisting of two A-type main-sequence stars with a combined apparent magnitude of around 4.1 separated by almost half an arcminute.[8]