Cool Stars 14 - Submitted Abstract # 222
This version created on 05 October 2006

Cool Stars in a hot place:  The early cluster environment of the Sun
and other low mass stars


Eric Gaidos, University of Hawaii

Infrared surveys of molecular clouds indicate that most stars form in
dense but loosely bound or unbound clusters that disperse in 1-10
Myr.  The presence of the products of short-lived radionuclides in
primitive meteorites strongly suggests a proximate supernova in early
Solar System history which in turn requires a dense stellar
environment for the primordial Sun.  Several previous investigators
have also used the dynamics of outer Solar System (OSS) bodies as a
constraint on the paleoenvironment of the Sun.  Here, I reconsider
those constraints in light of our evolving understanding of the
formation and evolution of the OSS, and show that the dynamics of
known OSS offers little or no constrain on plausible values of tides
and frequency of close stellar passages by stars.  However, the
presence or absence of yet more distant, undetected bodies may offer a
meaningful constrain on the dynamical environment of the nascent Sun.
I also present preliminary work to determine the statistical
properties of environments experienced by cluster stars using the
NBODY4 and NBODY6 codes.  Specifically, I examine the range of
possible histories experienced by solar-mass stars, including the
probability of capture into orbit around a Type I supernova
progenitor.  The simulations are also designed to determine
differences in those distribution with those of M stars due to mass
segregation in the cluster potential.  These different dynamical
histories equate to differences in fluxes of short-lived radionuclide
and ultraviolet radiation experienced by disks, with potential
consequences for planet formation.

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