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The largest complex in IC2574, region 9, is perhaps the most clear-cut example
of sequential star formation observationally. In comparing the registered FUV
and H images shown Fig. 6.11, a FUV source lacking spatially coincident H
emission is identi ed in the center of the complex. Several young, compact HII
regions surround this older cluster of OB stars. The FUV, H di erence image of
the region, shown in Fig. 6.12, provides a more dramatic picture of the in uence
of this complex on its surroundings. The FUV bright complex of massive stars in
the center is surrounded by six distinct areas of relatively younger star formation
represented by the H bright regions. Star formation is propagating outward from
the center of this complex in a spherical fashion.
Fig. 6.1. Registered H and FUV images of Holmberg II, region 6
