Recently , high-dispersion spectroscopy has demonstrated conclusively that four of the five globular clusters ( GCs ) in the Fornax dwarf spheroidal galaxy are very metal-poor with { [ Fe / H ] } < -2 .
The remaining cluster , Fornax 4 , has { [ Fe / H ] } = -1.4 .
This is in stark contrast to the field star metallicity distribution which shows a broad peak around { [ Fe / H ] } \approx - 1 with only a few percent of the stars having { [ Fe / H ] } < -2 .
If we only consider stars and clusters with { [ Fe / H ] } < -2 we thus find an extremely high GC specific frequency , S _ { N } \approx 400 , implying by far the highest ratio of GCs to field stars known anywhere .
We estimate that about 1/5–1/4 of all stars in the Fornax dSph with { [ Fe / H ] } < -2 belong to the four most metal-poor GCs .
These GCs could , therefore , at most have been a factor of 4–5 more massive initially .
Yet , the Fornax GCs appear to share the same anomalous chemical abundance patterns known from Milky Way GCs , commonly attributed to the presence of multiple stellar generations within the clusters .
The extreme ratio of metal-poor GC- versus field stars in the Fornax dSph is difficult to reconcile with scenarios for self-enrichment and early evolution of GCs in which a large fraction ( 90 % –95 % ) of the first-generation stars have been lost .
It also suggests that the GCs may not have formed as part of a larger population of now disrupted clusters with an initial power-law mass distribution .
The Fornax dSph may be a rosetta stone for constraining theories of the formation , self-enrichment and early dynamical evolution of star clusters .