Volume 552, April 2013
|Number of page(s)||6|
|Section||Galactic structure, stellar clusters and populations|
|Published online||04 April 2013|
The central density of R136 in 30 Doradus
European Southern Observatory,
Alonso de Cordova 3107 Vitacura Casilla
Accepted: 13 February 2013
The central density, ρ0, 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 ρ0. 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 ρ0 under reasonable and defensible assumptions about the IMF, finding ρ0 ≥ 1.5 × 104 M⊙/pc3 for the conservative assumption 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.
Key words: circumstellar matter / galaxies: clusters: individual: R 136 / stars: luminosity function, mass function / Magellanic Clouds / dust, extinction
© ESO, 2013
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