2012MNRAS.425L..91P

We examine the possibility that very massive stars greatly exceeding the commonly adopted stellar mass limit of 150 M_☉ may be present in young star clusters in the local universe. We identify 10 candidate clusters, some of which may host stars with masses up to 600 M_☉ formed via runaway collisions. We estimate the probabilities of these very massive stars being in eclipsing binaries to be ≳ 30 per cent. Although most of these systems cannot be resolved at present, their transits can be detected at distances of 3 Mpc even under the contamination of the background cluster light, due to the large associated luminosities ∼ 10⁷ L_☉ and mean transit depths of ∼ 10⁶ L_☉. Discovery of very massive eclipsing binaries would flag possible progenitors of pair-instability supernovae and intermediate-mass black holes.