MINESweeper: Spectrophotometric Modeling of Stars in the Gaia Era
  We present MINESweeper, a tool to measure stellar parameters by jointly
fitting observed spectra and broadband photometry to model isochrones and
spectral libraries. This approach enables the measurement of spectrophotometric
distances, in addition to stellar parameters such as Teff, log(g), [Fe/H],
[a/Fe], and radial velocity. MINESweeper employs a Bayesian framework and can
easily incorporate a variety of priors, including Gaia parallaxes. Mock data
are fit in order to demonstrate how the precision of derived parameters depends
on evolutionary phase and SNR. We then fit a selection of data in order to
validate the model outputs. Fits to a variety of benchmark stars including
Procyon, Arcturus, and the Sun result in derived stellar parameters that are in
good agreement with the literature. We then fit combined spectra and photometry
of stars in the open and globular clusters M92, M13, M3, M107, M71, and M67.
Derived distances, [Fe/H], [a/Fe], and log(g)-Teff, relations are in overall
good agreement with literature values, although there are trends between
metallicity and log(g), within clusters that point to systematic uncertainties
at the ~0.1 dex level. Finally, we fit a large sample of stars from the H3
Spectroscopic Survey in which high quality Gaia parallaxes are also available.
These stars are fit without the Gaia parallaxes so that the geometric
parallaxes can serve as an independent test of the spectrophotometric
distances. Comparison between the two reveals good agreement within their
formal uncertainties after accounting for the Gaia zero point uncertainties.
