Gamma Cassiopeiae and HR 266: A Massive Septuplet Illuminating the IC 59 and IC 63 Nebulae at d = 168 pc

The unusual prototype Be shell star gamma Cas is part of a triple system (WDS J00567+6043) that illuminates two arc-shaped nebulae: IC 59 and IC 63. The HR 266 system (WDS J00568+6022) is a massive quadruple lying 1274" away from gamma Cas (projected separation 1.0 pc), opposite of the reflection nebulae, which appears to be physically associated with this system based on common proper motion, radial velocity, and parallax. The entire gamma Cas system appears to constitute a massive septuplet (at least), with approximately 15 MSun in mass associated with the gamma Cas triplet, and about 13.5 MSun in mass associated with the HR 266 quadruplet. The gamma Cas system appears to be one of the highest multiplicity systems known (N=7).