Using numerical modeling and a grid of synthetic spectra, we examine the
effects that unresolved binaries have on the determination of various stellar
atmospheric parameters for SEGUE targets measured using the SEGUE Stellar
Parameter Pipeline (SSPP). To model undetected binaries that may be in the
SEGUE sample, we use a variety of mass distributions for the primary and
secondary stars in conjunction with empirically determined relationships for
orbital parameters to determine the fraction of G-K dwarf stars, as defined by
SDSS color cuts, that will be blended with a secondary companion. We focus on
the G-K dwarf sample in SEGUE as it records the history of chemical enrichment
in our galaxy. To determine the effect of the secondary on the spectroscopic
parameters, we synthesize a grid of model spectra from 3275 to 7850 K (~0.1 to
1.0 \msun) and [Fe/H]=-0.5 to -2.5 from MARCS model atmospheres using
TurboSpectrum. We analyze both "infinite" signal-to-noise ratio (S/N) models
and degraded versions, at median S/N of 50, 25 and 10. By running individual
and combined spectra (representing the binaries) through the SSPP, we determine
that ~10% of the blended G-K dwarf pairs with S/N>=25 will have their
atmospheric parameter determinations, in particular temperature and
metallicity, noticeably affected by the presence of an undetected secondary. To
account for the additional uncertainty from binary contamination at a S/N~10,
uncertainties of ~140 K and ~0.17 dex in [Fe/H] must be added in quadrature to
the published uncertainties of the SSPP. (Abridged)Comment: 68 pages, 20 figures, 9 table
