2001/08/17 by R. de la Fuente Marcos, C. de la Fuente Marcos
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:20011229
6 pages, 1 Postscript figure, LaTeX, uses A&A macros, submitted to A&A Main Journal
arxiv created 2001/08/17 · openalex publication_date 2001/12/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We use detailed numerical simulations and theoretical estimates to show that, if confirmed, the unusually brief microlensing events observed by If real, this dark cluster would be located between M 22 and the Galactic bulge and could include at least 10 6 substellar members with a typical size of 1-3 pc. Bound planets in wide or/and eccentric orbits are also able to reproduce the observed microlensing behaviour, but only if multiplanet systems (including large Kuiper-belt-like objects) are abundant, although, our calculations argue against the latter scenario as the ionization rate in M 22 is very high. Dynamically ejected or lone planets are, in principle, incompatible with the observational findings as they either escape their parent cluster in a relatively short time-scale after ejection or segregate toward the outskirts of the cluster. We discuss additional implications of the dark cluster scenario, including the existence of a population of RAMBOs toward the Galactic bulge.