Globular clusters ( GCs ) have been posited , alongside dwarf galaxies , as significant contributors to the field stellar population of the Galactic halo .
In order to quantify their contribution , we examine the fraction of halo stars formed in stellar clusters in the suite of 25 present-day Milky Way-mass cosmological zoom simulations from the E-MOSAICS project .
We find that a median of 2.3 and 0.3 per cent of the mass in halo field stars formed in clusters and GCs , defined as clusters more massive than 5 \times 10 ^ { 3 } and 10 ^ { 5 } ~ { } \mbox { M$ { } _ { \odot } $ } , respectively , with the 25 – 75 th percentiles spanning 1.9 – 3.0 and 0.2 – 0.5 per cent being caused by differences in the assembly histories of the host galaxies .
Under the extreme assumption that no stellar cluster survives to the present day , the mass fractions increase to a median of 5.9 and 1.8 per cent .
These small fractions indicate that the disruption of GCs plays a sub-dominant role in the build-up of the stellar halo .
We also determine the contributed halo mass fraction that would present signatures of light-element abundance variations considered to be unique to GCs , and find that clusters and GCs would contribute a median of 1.1 and 0.2 per cent , respectively .
We estimate the contributed fraction of GC stars to the Milky Way halo , based on recent surveys , and find upper limits of 2 – 5 per cent ( significantly lower than previous estimates ) , suggesting that models other than those invoking strong mass loss are required to describe the formation of chemically enriched stellar populations in GCs .