ITC Pizza Lunch

Date: 

Wednesday, April 11, 2018, 11:00am to 12:00pm

Location: 

Phillips

Ivan Cabrera (CfA), "The gas content of star clusters"

Abstract:  Studies during the last decade have revealed that nearly all Globular Clusters (GCs) host multiple populations (MPs) of stars with a distinctive chemical patterns in light elements. Young massive clusters (YMCs) have masses and densities similar to those expected of young GCs in the early universe, hence they are ideal places to test GC formation theories.
We present the latest constraints on the gas content of young ( 1-1000 Myr) star clusters. We find them to be gas free from very early ages, sometimes just after few Myr (even before the SNe). Also, they seem to remain this way throughout their lives (up to GC ages), in principle (based on escape velocity arguments), would be able to accrete and retain gas from the surrounding. This poses a severe handicap for the scenarios that try to explain MPs in GC by means of multiple SF event, as there seems to not be any fuel for such further star formation.

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Jill Naiman (ITC), "Should I Stay or Should I Go: Stellar Wind Retention and Expulsion in Star Clusters"

Abstract:  Mass and energy injection throughout the lifetime of a star cluster contributes to the gas reservoir available for subsequent episodes of star formation and the feedback energy budget responsible for ejecting material from the cluster.  In this talk I will discuss how the mass processed in stellar interiors and ejected as winds has the potential to augment the abundance ratios of currently forming stars, or stars which form at a later time from a retained gas reservoir. I will present the results of hydrodynamical simulations that explore a wide range of cluster masses, compactnesses, metallicities and stellar population age combinations in order to determine the range of parameter space conducive to stellar wind retention or wind powered gas expulsion in star clusters.  I will conclude with an overview of the effects of the assumed stellar wind prescription on the amounts of wind retention/expulsion at a given cluster evolutionary phase.

See also: Pizza Lunch, 2017-18