The central density of R136 in 30 Doradus

Abstract

The central density, .0, of a stellar cluster is an important physical parameter for determining its evolutionary and dynamical state. How much mass segregation there is or whether the cluster has undergone core collapse both depend on .0. We reanalyze the results of a previous paper that gives the mass density profile of R136 and combine them with both a conservative upper limit for the core parameter and a more uncertain recent measurement. We thus place a lower limit on .0 under reasonable and defensible assumptions about the IMF, finding .0 = 1.5 × 104 M·/pc3 for the conservative assumption a a < 0.4 pc for the cluster core parameter. If we use the lower, but more uncertain value a = 0.025 pc, the central density estimate becomes greater than 107 M·/pc3. A mechanism based on the destruction of a large number of circumstellar disks is posited to explain the hitherto unexplained increase in reddening presented in that same work. © 2013 ESO.