Kyle B. Johnston, Terry D. Oswalt, David Valls-Gabaud
Post main sequence (MS) mass-loss causes orbital separation amplification in
fragile (i.e., common proper motion) binary star systems. Components typically
have separations ~1000 a.u. Such wide pairs experience negligible mutual tidal
interactions and mass transfer between companions; they evolve as two separate
but coeval stars. In this paper we present models for how post-MS mass-loss
statistically distorts the frequency distribution of fragile binary
separations. These models demonstrate an expected increase in orbital
separation resulting from stellar mass-loss, as well as a perturbation of
associated orbital parameters. Comparisons between our models and observations
resulting from a known survey of visual binaries, specifically those containing
MS and white-dwarf pairs, demonstrate good agreement between calculated and
observed angular separation distributions.
View original:
http://arxiv.org/abs/1111.4100
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